protactic Meaning, Definition & Usage

Pro*tac"tic adjective

Etymology

Gr. placing or placed before, fr. to place in front; before + to arrange.

Definitions

1. Giving a previous narrative or explanation, as of the plot or personages of a play; introductory. Protactinium. A radioactive chemical element. Atomic symbol Pa; at. no. 91; at. wt. of longest-lived isotope, 231 (T½ = 32,500 yrs.) Also called brevium, Uranium X2 and UX2.