D defs.my
Entry 1 sense Webster, 1913

Protactic

/(prō̇*tăk"tĭk)/ · Pro·tac·tic · IPA
01 a. Giving a previous narrative or explanation, as of the plot or personages of a play; introductory.
  1. 1.
    Giving a previous narrative or explanation, as of the plot or personages of a play; introductory.