Definify.com
Webster 1913 Edition
Jack-in-a-box
Jack-in-a-box
.1.
(Bot.)
A tropical tree (
Hernandia sonora
), which bears a drupe that rattles when dry in the inflated calyx. 2.
A child’s toy, consisting of a box, out of which, when the lid is raised, a figure (usually a clown) springs; also called
jack-in-the-box
. 3.
(Mech.)
An epicyclic train of bevel gears for transmitting rotary motion to two parts in such a manner that their relative rotation may be variable; applied to driving the wheels of tricycles, road locomotives, and to cotton machinery, etc.; an equation box; a jack frame; – called also
compensating gearing
. 4.
A large wooden screw turning in a nut attached to the crosspiece of a rude press.