Longman Dictionary of Contemporary English
The Collaborative International Dictionary
altar boy \al"tar boy\, n. a boy who assists a priest at the clebration of the Holy Mass and other forms of public worship; -- also called acolyte.
Wiktionary
n. 1 A boy serving as an acolyte in certain forms of Christianity. 2 A young man, adhering to traditional values.
WordNet
n. a boy serving as an acolyte
Usage examples of "altar boy".
And if I continued to gratify Gusewski with my services as an altar boy, it was only in order to gaze at Mahlke's neck during holy communion.
I stood in the front door until the priest was gone and the altar boy.
Danlo thought he was both cynical and sincere, too aware of the darkness that everywhere permeated the universe and yet strangely innocent, almost like a bright-eyed altar boy who stands before the Edic lights at a vastening ceremony and is forced to ponder mysteries he is too young to comprehend.
An altar boy in gleaming white surplice and red cassock scurried up beside Duncan and tugged at his sleeve urgently, and Duncan moved off to take his place in the procession.
Up to this point, his promise had been only the words of an altar boy.