\Sub*p[oe]"na\, n. [NL., fr. L. sub under + poena
punishment. See {Pain}.] (Law)
A writ commanding the attendance in court, as a witness, of
the person on whom it is served, under a penalty; the process
by which a defendant in equity is commanded to appear and
answer the plaintiff's bill. [Written also {subpena}.]
{Subp[oe]na ad testificandum}. [NL.] A writ used to procure
   the attendance of a witness for the purpose of testifying.
{Subp[oe]na duces tecum}. [NL.] A writ which requires a
   witness to attend and bring certain documents.

\Sub*p[oe]"na\, v. t. [imp. & p. p. {Subp[oe]naed}; p.
pr. & vb. n. {Subp[oe]naing}.] (Law)
To serve with a writ of subp[oe]na; to command attendance in
court by a legal writ, under a penalty in case of
disobedience.