It all depends how you define the word "participate."

While that may seem as silly as bickering over the definition of the word "is," the implications for some oil company executives who testified at a Senate hearing could be significant. Based on how the word is parsed, some executives either told the truth or did not when they were asked about their "participation" in the 2001 energy task force headed by Vice President Cheney.

The dispute stems from a question raised by Sen. Frank Lautenberg (D-N.J.). At a hearing two weeks ago, he asked five oil executives whether they or representatives of their companies participated in meetings with Cheney's energy task force.

The chief executives of Exxon Mobil Corp., ConocoPhillips Co. and Chevron Corp. answered no. The president of Shell Oil Co. said his company did not participate "to my knowledge," and the chief of BP America Inc. said he did not know.

The Bush administration has refused to identify who participated in the task force meetings. But The Washington Post reported last week that a White House document shows that in 2001, officials from Exxon Mobil, Conoco (before its merger with Phillips), Shell Oil and BP America met in the White House complex with the Cheney aides who were developing a national energy policy, parts of which became law and parts of which are still being debated.

Yesterday, Marnie Funk, a spokeswoman for the GOP staff of the Senate Energy and Natural Resources Committee, one of the two panels that convened the hearing, said its lawyers had reached a preliminary conclusion: Based on a court decision in which two groups unsuccessfully challenged the secrecy of the Cheney task force, Funk said the executives appeared to be telling the truth.

"What we simply determined was that the definition of 'participation' was something litigated, and what the court concluded was that attending meetings, and even making presentations, did not rise to the level of fully participating," Funk said.

Lautenberg sees it differently, and disputes the GOP interpretation of the court decision. He also said Republicans are incorrectly interpreting his question.

"I think we're getting down to almost a silly discussion," Lautenberg said.

Lautenberg said that when he asked the question, he was thinking of the word "participation" in broad terms. Here's his definition: "If you're doing anything more than breathing in the room when you're there. Even if you're a silent observer."

The senator has asked the Justice Department to look into the matter.

Funk said that the GOP staff's findings have given "considerable comfort" to Sen. Pete V. Domenici (R-N.M.), the chairman of the energy panel. Funk said Domenici is reserving final judgment until after he has reviewed the written clarification that he and the panel's ranking Democrat, Sen. Jeff Bingaman (N.M.), have asked the oil companies to submit.

Yesterday, Exxon released a response to the senators, reiterating its position that its chief executive, Lee R. Raymond, testified accurately. The statement said the company had not "been a participant on the Task Force and no representative of ExxonMobil attended any meeting of the Task Force."

The statement went on to say that on Feb. 14, 2001, a 45-minute meeting took place with "an administration official" at Exxon Mobil's request. The company "provided information on the global energy supply and demand situation and steps ExxonMobil was taking to meet the world's growing energy needs."

Chevron recently submitted a statement saying that its employees had not participated in meetings with the task force. But the company said it sent a letter to President Bush outlining its position on energy policies.

ConocoPhillips has said its chief executive was appointed when Conoco and Phillips merged in 2002 and was unaware that Conoco officials had met with task force staff.

Ross Pillari, CEO of BP America Inc. David O'Reilly, CEO of Chevron Corp. James J. Mulva, CEO of ConocoPhillips Co. Lee R. Raymond, CEO of Exxon Mobil Corp.John Hofmeister, president of Shell Oil Co.