Webster's Revised Unabridged Dictionary · 1913

Lab

Lab , intransitive verb

[Compare OD. labben to babble.]

To prate; to gossip; to babble; to blab. [Obsolete] — Chaucer

lab , noun

1.
A telltale; a prater; a blabber. [Obsolete]
I am no lab. — Chaucer
2.
Laboratory. [Colloquial]

lab , adjective

Of or pertaining to a laboratory; as, a lab bench. [Colloquial]