Acer negundo

(idiomatic) Crazy; unhinged; irrational. / (idiomatic) Stoned or intoxicated.

(UK, slang) Crazy; unhinged; irrational. / (UK, idiomatic) Stoned or intoxicated.

A uniquely addressable lockable box located on the premises of a post office that may be hired as collection point for mail. / (electricity) A test instrument once used by telephone engineers.

plural of post office box

plural of black-box function

(optimization) A function whose closed-form expression is not known or does not exist, and whose properties cannot be inferred.

Someone who plays the cigar box guitar.

plural of cigar box guitarist

(music) A simple guitar-like string instrument that uses a cigar box as a resonator, and traditionally has a broomstick for a neck.