(1):

(n.) One who is bound by indentures or by legal agreement to serve a mechanic, or other person, for a certain time, with a view to learn the art, or trade, in which his master is bound to instruct him.

(2):

(n.) One not well versed in a subject; a tyro.

(3):

(n.) A barrister, considered a learner of law till of sixteen years' standing, when he might be called to the rank of serjeant.

(4):

(v. t.) To bind to, or put under the care of, a master, for the purpose of instruction in a trade or business.