Definitions

Subpoena:.the usual writ for the summoning of witnesses or the submission of evidence, as records or documents, before a court or other deliberative body.
subpoena (n.)

1422, sub pena, from M.L. sub poena "under penalty," the first words of the writ commanding the presence of someone under penalty of failure, from L. sub "under" + poena, ablative of poena "penalty." The verb is attested from 1640.

subpoena
noun
1.	a writ issued by court authority to compel the attendance of a witness at a judicial proceeding; disobedience may be punishable as a contempt of court

Gonzales
“You ignored the subpoena, did not come forward today, did not produce the documents and did not even offer an explanation for your noncompliance,” the senators wrote in a lettter to Alberto Gonzales today. “Your action today is in defiance of the Committee’s subpoena without explanation of any legal basis for doing so.
Those senators btw are Alren Spector and Patrick Leahy.