Signal \Sig"nal\, n. [F., fr. LL. signale, fr. L. signum. See Sign, n.]

1. A sign made for the purpose of giving notice to a person of some occurence, command, or danger; also, a sign, event, or watchword, which has been agreed upon as the occasion of concerted action.

All obeyed The wonted signal and superior voice Of this great potentate. --Milton.

2. A token; an indication; a foreshadowing; a sign.

The weary sun . . . Gives signal of a goodly day to-morrow. --Shak.

There was not the least signal of the calamity to be seen. --De Foc.

Source: Webster's Revised Unabridged Dictionary (1913)
 

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)
 

Signal \Sig"nal\, a. [From signal, n.: cf. F. signal['e].]

1. Noticeable; distinguished from what is ordinary; eminent; remarkable; memorable; as, a signal exploit; a signal service; a signal act of benevolence.

As signal now in low, dejected state As erst in highest, behold him where he lies. --Milton.

2. Of or pertaining to signals, or the use of signals in conveying information; as, a signal flag or officer.

The signal service, a bureau of the government (in the United States connected with the War Department) organized to collect from the whole country simultaneous raports of local meteorological conditions, upon comparison of which at the central office, predictions concerning the weather are telegraphed to various sections, where they are made known by signals publicly displayed.

Signal station, the place where a signal is displayed; specifically, an observation office of the signal service.

Syn: Eminent; remarkable; memorable; extraordinary; notable; conspicuous.

Source: Webster's Revised Unabridged Dictionary (1913)