from
The Collaborative International Dictionary of English v.0.48
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.
[1913 Webster]
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}.
[1913 Webster]
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}.
[1913 Webster]
4. A large wooden screw turning in a nut attached to the
crosspiece of a rude press.
[1913 Webster]