The Collaborative International Dictionary of English v.0.48:

Line-up \Line"-up`\, Lineup \Line"up`\ (l[imac]n"[u^]p), n.
   1. The members of a team who are scheduled to play a game.
      [PJC]

   2. Specifically: The formation of football players before the
      start or a restart of play.
      [PJC]

   3. Specifically: (baseball) a list of batters in the order in
      which they will bat. [WordNet sense 1]

   Syn: batting order, card, lineup.
        [WordNet 1.5]

   4. Hence: any arrangement of persons (rarely, of things),
      esp. when having a common purpose or sentiment; as, the
      line-up at a ticket-office window; the line-up of
      political factions. [Colloq.]
      [PJC]

   5. A group of persons including a suspect in a police
      investigation, arranged so as to be observed by a witness,
      who is requested to identify the perpetrator, if he/she is
      present in the group. Such an identification may be used
      as evidence of guilt of the suspect. Also called a police
      lineup. [WordNet sense 2]
      [PJC]