Signal \Sig"nal\, v. t. [imp. & p. p. Signaled or Signalled; p. pr. & vb. n. Signaling or Signalling.]

1. To communicate by signals; as, to signal orders.

2. To notify by a signals; to make a signal or signals to; as, to signal a fleet to anchor. --M. Arnold.

Source: Webster's Revised Unabridged Dictionary (1913)