Meaning of ad libitum

ad lib•i•tum

Pronunciation: (ad lib'i-tum Lat. äd lib'i-t&oobrevem&sec), [key]
  1. at one's pleasure.
  2. not obligatory or indispensable. Abbr.: ad lib.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.