Concise Bible Dictionary:
The Lord was the Bridegroom, and while He was on earth the “sons” (companions, friends) of the bridechamber could not mourn nor fast; but in His absence they would do so (Matt. 9:15; Mark 2:19; Luke 5:34). The friend of the Bridegroom (to whom John the Baptist likened himself) is spoken of in distinction from the bride herself (John 3:29).
Strong’s Dictionary of Greek Words:
Meaning:
from 3565; the bridal room