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" (from nasalized form of PIE root *pete- "to spread"). Related: Expanded; expanding.
It forms all or part of: compass; El Paso; expand; expanse; expansion; expansive; fathom; pace (n.); paella; pan (n.); pandiculation; pas; pass; passe; passim; passacaglia; passage; passenger; passport; paten; patent; patina; petal; spandrel; spawn.
It is the hypothetical source of/evidence for its existence is provided by: Greek petannynai "to spread out," petalon "a leaf," patane "plate, dish;" Old Norse faðmr "embrace, bosom," Old English fæðm "embrace, bosom, fathom," Old Saxon fathmos "the outstretched arms."
"expand or increase rapidly; rise suddenly in position or rank," 1741, from mushroom (n.). Related: Mushroomed; mushrooming.
late 14c., dilaten, "describe at length, speak at length," from Old French dilater and directly from Late Latin dilatare "make wider, enlarge," from dis- "apart" (see dis-) + lātus "broad, wide, widespread, extended" (see latitude). Meaning "expand, distend, spread out, enlarge in all directions" (transitive) is from early 15c.; intransitive sense of "spread out, expand, distend" also is from early 15c. A doublet of delay. Related: Dilated; dilating.