OPINION
SHORT, Judge.Respondent Carl Moore was charged with possessing with an intent to distribute a controlled substance containing three or more grams of cocaine base. Moore moved to have the relevant statute declared unconstitutionally void for vagueness because the statute used the undefined term “cocaine base.” The trial court granted respondent’s motion and the state appeals. We disagree and reverse the trial court’s ruling.
FACTS
On February 15, 1988, members of the Minneapolis Police Department’s Crack Enforcement Team, in possession of a valid search warrant, entered a house located in south Minneapolis. The officers observed respondent Carl Moore sitting on a bed in a front bedroom. Beside Moore was a .357 Magnum pistol and a plastic bag containing 40 small bundles of what the criminal complaint calls a “crack-like” substance. The officers also found $476.00 in small denominations on the bed and a large assortment of drug paraphernalia in the rooms of the house. The officers arrested Moore and seized the drugs and the other evidence.
The police department had the seized substance tested by the city chemist. She determined that the substance was crack-cocaine weighing 6.25 grams. The state charged Moore, pursuant to Minn.Stat. § 152.01, subds. 4 and 10, § 152.02, subd. 3(l)(d), § 152.09, subd. 1(1) and § 152.15, subd. 1(2) (1986), with intent to manufacture, sell or otherwise distribute a controlled substance. Two months later, in April of 1988, the state amended its complaint to include the charge of possession with the intent to sell a mixture of a controlled substance containing three or more grams of “cocaine base”,1 in violation of Minn.Stat. § 152.15, subd. l(l)(i) (Supp. 1987), a new statute passed by the 1987 legislature. By thus amending the complaint, the state increased the severity level of the charged offenses against Moore from a level VI offense to a level VII offense for purposes of sentencing. See Minnesota Sentencing Guidelines V.
Moore tried to plead guilty to the original lesser charge, but the state would not accept his plea. Moore brought a motion, pursuant to Minn.R.Crim.P. 17.06, subd. 2(2)(c), to have the new statute under which he was charged declared unconstitutional. The trial court concluded the statute was unconstitutionally vague because the legislature had not defined the term “cocaine base” and because the meaning of that term is not apparent to a person of ordinary intelligence.
ISSUE
Is Minn.Stat. § 152.15, subd. l(l)(i) (Supp.1987) void for vagueness because it uses the undefined term “cocaine base?”
*567ANALYSIS
Minn.Stat. § 152.15, subd. 1 (Supp.1987) provides criminal penalties for conviction of possession with intent to sell specified controlled substances, including a “mixture containing three grams or more of cocaine base.” Cocaine is defined in Minn.Stat. § 152.02, subd. 3(l)(d) (1986) as:
(d) Coca leaves and any salt, compound, derivative, or preparation of coca leaves, and any salt, compound derivative, or preparation thereof which is chemically equivalent or identical with any of these substances, except that the substances shall not include decocainized coca leaves or extraction of coca leaves, which extractions do not contain cocaine or ecgo-nine.
However, the legislature did not define the term “cocaine base.” Moore argues, and the trial court concluded, that without a definition for that term, the statute is constitutionally infirm.
I.
The construction of a statute is a question of law for the court, and is subject to de novo review on appeal. Hibbing Education Association v. Public Employment Relations Board, 369 N.W.2d 527, 529 (Minn.1985); Matter of Welfare of 416 N.W.2d 142, 146 (Minn.Ct.App.1987). We therefore need not defer to the findings drawn by the trial court regarding the validity of Minn.Stat. § 152.15, subd. l(l)(i) (Supp.1987).
One who challenges the constitutionality of a statute must overcome every presumption in favor of its constitutionality. Miller Brewing Co. v. State, 284 N.W.2d 353, 356 (Minn.1979), Matter of Martenies, 350 N.W.2d 470, 473 (Minn.Ct.App.1984) pet. for rev. denied (Minn. Sept. 12, 1984); see also Minn.Stat. § 645.17(3) (1986) (courts required to presume the legislature did not intend to violate the constitution of the United States or of this state). The power of an appellate court to declare a statute unconstitutional is to be exercised only when absolutely necessary and then with extreme caution. Wegan v. Village of Lexington, 309 N.W.2d 273, 279 (Minn.1981); City of Richfield v. Local No. 1215 International Association of Fire Fighters, 276 N.W.2d 42, 45 (Minn.1979).
II.
A criminal statute will not be found void for vagueness unless it fails to define the criminal offense with sufficient definiteness that ordinary people can understand what conduct is prohibited and in a manner that does not encourage arbitrary and discriminatory enforcement. Kolender v. Lawson, 461 U.S. 352, 357, 103 S.Ct. 1855, 1858, 75 L.Ed.2d 903 (1983); State v. Newstrom, 371 N.W.2d 525, 528 (Minn.1985); State v. Skinner, 403 N.W.2d 912, 915 (Minn.Ct.App.1987). The United States Supreme Court recently explained in Kolen-der the importance of the second requirement.
Although the [void for vagueness] doctrine focuses both on actual notice to citizens and arbitrary enforcement, we have recognized recently that the more important aspect * * * “is ... the requirement that a legislature establish minimal guidelines to govern law enforcement.”
Kolender, 461 U.S. at 357-58, 103 S.Ct. at 1858 (quoting Smith v. Goguen, 415 U.S. 566, 574, 94 S.Ct. 1242, 1248, 39 L.Ed.2d 605 (1974)). Moore does not claim, nor could he claim, that the statute in question invites arbitrary enforcement. However, he argues that a person of average intelligence could not discern the meaning of “cocaine base” by reading the language of the statute. He notes that while the legislature has provided an extensive definition of cocaine, and also of other substances criminalized by the controlled substances statutes, it neglected to include a definition of “cocaine base.” Moore claims that because the term is undefined, the ordinary person is kept guessing as to its meaning.
In deciding whether the term “cocaine base” renders the statute unconstitutional, we are guided by the well-settled rule that a statute, if it can be made constitutionally definite by a reasonable construction, must be given that construction by this court. United States v. Harriss, 347 U.S. 612, *568618, 74 S.Ct. 808, 812, 98 L.Ed. 989 (1964); United States v. Thomas, 567 F.2d 299, 300 (5th Cir.1978). Words of a statute are to be given their ordinary meaning in the absence of persuasive reasons to the contrary. Burns v. Alcala, 420 U.S. 575, 580-81, 95 S.Ct. 1180, 1184-85, 43 L.Ed.2d 469 (1975). Indeed, where a statute is ambiguous, a construction which avoids constitutional conflict should be given, even though it is less natural. United States v. Rivera, 427 F.Supp. 89, 92 (S.D.N.Y.1977).
An undefined word or phrase renders a statute constitutionally infirm only when the meaning of that word or phrase is neither commonly understood nor established by judicial construction in other statutes. See e.g., United States v. Delahoussaye, 573 F.2d 910, 912-13 (5th Cir.1978); Minnesota Wood Specialities, Inc. v. Mattson, 274 N.W.2d 116, 119 (Minn.1978). In United States v. Thomas, 567 F.2d at 300, the federal appeals court affirmed the trial judge’s conclusion that the word “silencer,” used in a statute prohibiting the possession and transfer of certain firearms, was not so vague as to require a statutory definition in order to satisfy due process. The appeals court concluded that “silencer” had a commonly accepted meaning which should be used in construing the statute. A person of ordinary intelligence could therefore understand the form of conduct the statute was intended to prohibit. Id.
We think a similar level of general understanding may be attributed to the meaning of the words “cocaine” and “base.” Moore introduces an artificial complexity into this case when he urges that “cocaine base” must be read as an indivisible phrase with an indeterminate meaning rather than as two words, each with an ordinary meaning. Moore does not dispute that cocaine has a clear meaning, as given in Minn.Stat. § 152.02, subd. 3(l)(d). The word “base,” though not defined in the prohibited drug statutes, also has an ordinary meaning when used to describe a chemical substance. Webster’s Dictionary defines “base” as “the chief active ingredient ... the predominating substance ... left as a residue on refining.” Webster’s 3rd New International Dictionary p. 180 (unabridged) (1986). The American Heritage Dictionary defines “base” as “[a] fundamental ingredient” or “chief constituent.” The American Heritage Dictionary 160 (2d ed. 1982).
The legislature thus used the word “base” in accordance with its standard dictionary definition to describe the refined form of cocaine; chemically it consists of the cocaine molecule without a hydrogen-chloride molecule bonded to it. An ordinary person of average intelligence would not have been greatly helped if, instead of the term “cocaine base,” the legislature had used the chemical formula for refined cocaine (C17H21O4) to describe the substance in question. Although the street term “crack” might be more clear to some drug dealers, that term is less scientifically precise. Furthermore, the legislature has not used street terms to describe other controlled substances, even though terms such as “pot” or “horse” may be used more commonly by drug dealers than the words “marijuana” or “heroin.”
We also note that other courts, when addressing issues involving the possession and sale of undiluted or crack cocaine, have been clear as to the meaning of “cocaine base.” The defendant in United States v. Smith, 840 F.2d 886 (11th Cir.1988) challenged his conviction under a federal statute making it illegal to “knowingly and intentionally possess with intent to distribute 5 grams or more of a mixture containing cocaine base.” Id. at 888; see also 21 U.S.C.A. § 841(a)(l)(1981). Smith alleged the definition of the word “mixture” was too vague and that, because of this vagueness, he may not have possessed more than five grams. The federal appeals court rejected Smith’s argument, concluding that punishment under the statute merely required that the weight of the mixture meets or exceeds five grams, and “that cocaine base be a component of the mixture.” United States v. Smith, 840 F.2d at 889. Although the definition of “cocaine base” was not specifically challenged, the Smith court necessarily assumed the term had a clear meaning in order to conclude that the statute was not vague. See also *569United States v. Collado-Gomez, 834 F.2d 280, 280 (2nd Cir.1987) (equating the word “cocaine base” with “crack”); United States v. Levy, 703 F.2d 791, 795 (4th Cir.1983) (identifying “pure cocaine” as “cocaine base”).
While the legislature might have removed the slightest possibility of confusion by including a definition for the composite term “cocaine base” in the definition section of the prohibited drugs statutes, its failure to do so does not render Section 152.15, subd. 1(1)® constitutionally infirm. We think a person of average intelligence will understand that “cocaine base,” the possession and sale of which evokes a greater criminal penalty than the possession and sale of the same quantity of other forms of cocaine, means pure cocaine in its undiluted chemical form. The word “cocaine,” as Moore concedes, is adequately defined in Minn.Stat. § 152.02, subd. 3(l)(d). The word “base” can be understood for the purposes of this statute according to its common dictionary definition. Because “cocaine base” is not vague, and because the statute as a whole establishes adequate guidelines to govern law enforcement, we- conclude that Minn.Stat. § 152.15, subd. 1(1X9 satisfies due process requirements and is not void for vagueness under either the federal or the state constitution.
DECISION
The term “cocaine base” is not so vague as to render Minn.Stat. § 152.15, subd. l(l)(i) (Supp.1987) constitutionally infirm. The statute defines the offense for which the criminal penalty attaches with sufficient definiteness that ordinary people can understand what conduct is prohibited. The trial court is therefore reversed.
REVERSED.
RANDALL, J., dissents.
. The only place that the term “cocaine base” appears in the statutes is in the penal provision, § 152.15, subd. l(l)(i), which was added by the 1987 legislature.