'Groomsman' definitions:

Definition of 'groomsman'

(from WordNet)
noun
A male attendant of the bridegroom at a wedding

Definition of 'Groomsman'

From: GCIDE
  • Groomsman \Grooms"man\, n.; pl. Groomsmen. A male attendant of a bridegroom at his wedding; -- the chief attendant is also called the best man; -- the correlative of bridesmaid. [1913 Webster]