early 15c., "spread out, open out, spread flat, extend widely;" also transitive, "cause to grow larger;" from Anglo-French espaundre, Old French espandre "spread, spread out, be spilled," and directly from Latin expandere "to spread out, unfold, expand," from ex- "out" (see ex-) + pandere "to spread, stretch" (see pace, n.). Related: Expanded; expanding.