Etymology

Noun

1. The adult male of the red deer (Cervus elaphus), a large European species closely related to the American elk, or wapiti.
2. The male of certain other species of large deer.
3. A colt, or filly.
4. A romping girl.
5. An improperly or late castrated bull or ram; -- called also a bull seg. See the Note under ox.
6. An outside irregular dealer in stocks, who is not a member of the exchange.
7. One who applies for the allotment of shares in new projects, with a view to sell immediately at a premium, and not to hold the stock.
8. The European wren.
9. An unmarried male, a bachelor; a male not accompanying a female at a social event.
10. 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

Verb

1. To act as a "stag", an irregular dealer in stocks.
2. To watch; to dog, or keep track of.

Adverb

1. Of a man, attending a formal social function without a date.

   My brother went stag to prom because he couldn't find a date.