Originally, and literally, a bone fire burned at mid-summer. During Bealtinne (see also Beltaine), in Celtic mythology, fires were burned on the hills. People herded their stock through the fires and jumped the fires themselves, then retired to the farther hills for fertility acts.

Now any large, outdoor fire which celebrates anything from football games to a summer beach party.

Bon"fire` (?), n. [OE. bonefire, banefire, orig. a fire of bones; bone + fire; but cf. also Prov. E. bun a dry stalk.]

A large fire built in the open air, as an expression of public joy and exultation, or for amusement.

Full soon by bonfire and by bell, We learnt our liege was passing well. Gay.

 

© Webster 1913.