(1):

(n.) A clergyman who is officially attached to the army or navy, to some public institution, or to a family or court, for the purpose of performing divine service.

(2):

(n.) Any person (clergyman or layman) chosen to conduct religious exercises for a society, etc.; as, a chaplain of a Masonic or a temperance lodge.

(3):

(n.) An ecclesiastic who has a chapel, or who performs religious service in a chapel.