What does "elater" mean?

Additional senses

1. 2.(Zoöl.) Any beetle of the family Elateridæ, having the habit, when laid on the back, of giving a sudden upward spring, by a quick movement of the articulation between the abdomen and thorax; -- called also click beetle, spring beetle, and snapping beetle.
2. 3.(Zoöl.) The caudal spring used by Podura and related insects for leaping. See Collembola.
3. 4.The active principle of elaterium, being found in the juice of the wild or squirting cucumber (Ecballium agreste, formerly Motordica Elaterium) and other related species. It is extracted as a bitter, white, crystalline substance, which is a violent purgative.