INTRODUCTION

The judiciary says what a statute means1 in order "to give effect to the law" a legislature enacted.2 To this end, courts "read the statute according to its text."3 If the legislature did not define a particular word, courts generally look to the ordinary meaning of the word used4 at the time the legislature adopted the statute.5 This interpretive method-commonly called the "ordinary-meaning canon"6-assumes that a word's ordinary meaning most "accurately expresses the legislative purpose."7

This inquiry sounds simple enough: courts merely ask how a word is (or was) ordinarily understood. As one professor put it, the ordinary meaning is "that which an ordinary speaker of the English language-twin sibling to the common law's reasonable person-would draw from the statutory text."8 But putting the theory into practice can be difficult.

In the last few decades, lawyers and judges have increasingly used dictionaries to determine a word's ordinary meaning.9 For example, the ordinary-meaning canon was on display in Muscarello v. United States,10 when the U.S. Supreme Court consolidated two criminal cases.11 In one case, Frank Muscarello was arrested after driving to a drug deal with a handgun locked in his truck's glove compartment.12 In the other case, which had similar facts, the defendants had stored their guns in the car's trunk.13 In both lower court opinions, the courts of appeals found that the defendants had violated 18 U.S.C. § 924(c)(1) because they "'carrie[d]' the guns during and in relation to a drug trafficking offense."14 The issue was whether the ordinary meaning of the phrase "carries a firearm" included storing handguns in a vehicle's locked compartment.15

The Supreme Court looked to a number of sources in its attempt to discern the phrase's ordinary meaning. First, the Court looked to the Oxford English Dictionary.16 Then it consulted Webster's Third New International Dictionary, the Random House Dictionary of the English Language Unabridged, the Barnhart Dictionary of Etymology, the Oxford Dictionary of English Etymology, the King James Bible, Robinson Crusoe, and Moby Dick.17 The Court also cited articles from the New York Times, the Boston Globe, the Colorado Springs Gazette Telegraph, and the Arkansas Gazette.18 After reviewing all these sources (and others), the Court determined that the ordinary meaning of "carrying a firearm" included driving a car with a gun in it.19 The dissent also conducted an extensive search for the word's ordinary meaning by consulting a legal dictionary, several translations of the Bible, poems, and scripts from the film The Magnificent Seven and the television shows M·A·S·H and Sesame Street.20 The ordinary-meaning analysis of both opinions seemed somewhat haphazard.

To bring more statistical analysis to the ordinary-meaning canon, then-law student Stephen Mouritsen,21 who held a master of arts in linguistics with an emphasis in corpus linguistics,22 thought of a better way. He proposed using corpus linguistics23-the study of language through collections of spoken or written texts, called corpora.24 These collections typically take the form of digitized databases that are accessible through an online interface.25 A user can search the corpus-linguistics database for a particular word or phrase to study how that word or phrase has actually been used in the texts collected in the corpus.26

One corpus-linguistics database is the Corpus of Contemporary American English ("COCA"), which "is the largest freely-available corpus of English."27 The COCA contains more than 520 million words and is equally divided among transcriptions of spoken language,28 fiction publications,29 popular magazines,30 newspapers,31 and academic texts.32 Professor Mark Davies, a corpus linguist, developed the COCA through his academic work at Brigham Young University.33 The COCA is a "tagged corpus,"34 which means that each word is labeled in reference to its particular part of speech-for example, a noun or a verb. …