Explanatory
来自Big Physics
wiktionary
From Middle English explanen, from Old French explaner, from Latin explanō(“I flatten, spread out, make plain or clear, explain”), from ex-(“out”) + planō(“I flatten, make level”), from planus(“level, plain”); see plain and plane. Compare esplanade, splanade. Displaced native Middle English arecchen, irecchen(“to explain, expound”) (from Old English āreccan, ġereccan).
etymonline
explanatory (adj.)
"serving to explain, containing explanation," 1610s, from or modeled on Late Latin explanatorius "having to do with an explanation," from Latin explanat-, past-participle stem of explanare "make plain or clear" (see explanation).
