The wheels of justice move slowly sometimes, but not, apparently, as slowly as Webster’s New World Dictionary.

Slang has always been a challenge for the courts in cases that involve vulgar or insulting language. Conventional dictionaries lag the spoken word by design. That has lawyers and judges turning to a more fluid source of definitions: Urban Dictionary, a crowdsourced collection of slang words on the Internet.

The online site, created by a college freshman in 1999, has found itself in the thick of cases involving everything from sexual harassment to armed robbery to requests for personalised license plates, as courts look to discern meaning and intent in the modern lexicon.

Last month, Urban Dictionary was cited in a financial restitution case in Wisconsin, where an appeals court was reviewing the term “jack” because a convicted robber and his companion had referred to themselves as the “jack boys”.

The court noted that according to Urban Dictionary, “jack” means “to steal, or take from an unsuspecting person or store”. It rejected the convicted man’s claim that he should not have to make restitution to the owner of a van he stole to use in a robbery.

Two weeks earlier, a court in Tennessee noted that a phrase used by a manager at a supply chain logistics company “to nut” was defined by Urban Dictionary as “to ejaculate”. After weighing that and other evidence, it rejected a motion to dismiss a sexual harassment claim by female employees.

It can take years for slang terms to be included in traditional dictionaries, whose editors want to be certain that the words have staying power. By contrast, some new words rush into Urban Dictionary in less than a day. As a result, the site has cropped up in dozens of court cases in recent years, according to a Lexis database of federal and State cases, though the outcome rarely rests solely on a definition.

This trend is likely to accelerate, according to Greg Lastowka, a professor of law at Rutgers specialising in Internet and property law. “If it is Urban Dictionary or hire some linguistic expert to do a survey, it seems like a pretty cheap, pretty good alternative for the court,” he said.

In the last year alone, the website was used by courts to define iron (“handgun”); catfishing (“the phenomenon of Internet predators that fabricate online identities”); dap (“the knocking of fists together as a greeting, or form of respect”); and grenade (“the solitary ugly girl always found with a group of hotties”).

Reference in legal cases to Urban Dictionary and Wikipedia, the online encyclopaedia, have become common enough that in its Spring 2010 issue, the law review of St. John’s University in Queens published an article that tried to create standardised rules for the most appropriate uses of crowdsourced websites.

Wisdom of the crowd

Scientific terms and other technical definitions should not be culled from such sites, the article concluded, but it added, “The wisdom of the crowd is an appropriate and valuable reference when consensus itself is at issue, the information is generally known or the content is easily verifiable.”

Urban Dictionary’s move into the legal arena surprises no one more than Aaron Peckham (32), its founder, who has continued to run it like a homegrown business. Mr. Peckham, who lives in San Francisco, has never taken venture capital money and still runs the entire site from his laptop.

When he began the site in 1999 at California Polytechnic State University, it was meant to be a parody. “Friends and I would sit around and make up words,” he said. As the Internet grew in size, however, contributors from around the globe began to join in and enforce a kind of democratic evaluation of the words.

Urban Dictionary currently gets 110 million monthly page views and is the 77th biggest website in the country, according to Quantcast, a Web analytics company.

Roughly 2.3 million definitions posted on the site — some crude or insensitive — and about 30,000 proposed new definitions are sent in each month, Mr. Peckham said. For one to be added, at least five other site members must vote for it — from roughly 7,000 users a month who click “publish” or “don’t publish”. Despite the low threshold, some two-thirds of proposals are rejected, Mr. Peckham estimates.

Sometimes a common slang meaning has nothing to do with what a person actually meant. In 2009, the Nevada Supreme Court said that the Department of Motor Vehicles could not deny the personalised license plate “HOE” because Urban Dictionary said it meant prostitute. “A reasonable mind would not accept the Urban Dictionary entries alone as adequate to support a conclusion that the word ‘HOE’ is offensive or inappropriate,” the justices wrote.

In fact, William Junge said that he wanted the plate for his Chevrolet Tahoe only because “TAHOE” was not available. Mr. Junge (62 at the time) said the idea that it could mean whores had not crossed his mind.

“That was their interpretation. Shame on them.” — New York Times News Service