Lăr'um, n.

(Synop., § 130), n. [Abbreviation of alarum, for alarm, q. v.]

1. Any thing used for giving an alarm or notice, as at particular times; an alarm.
2. Alarm; a noise giving notice of danger. [R.]

Of this nature was that larum, which, though it were but three inches big, yet would both wake a man and of itself light a candle for him at any set hour. Wilkins.