(countable, usually attributive) An unmarried male, a bachelor; a male not accompanying a female at a social event.
a stag dance; a stag party
(countable) A social event for males held in honor of a groom on the eve of his wedding, attended by male friends of the groom, sometimes a fund-raiser.
The stag will be held in the hotel's ballroom.
(countable) A stag beetle (family Lua error in Module:parameters at line 780: Parameter "noshow" is not used by this template.).
2007, Eric R. Eaton, Kenn Kaufman, Kaufman Field Guide to Insects of North America (page 132)
Members of the genus Pasimachus[…] can be confused with stag beetles […] but stags have elbowed antennae.
Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing. (See the entry for “stag”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.)