Why is the ninth month called September?
"to plait, knit, weave, twist together," c.1200, breidan, from Old English bregdan "to move quickly, pull, shake, swing, throw (in wrestling), draw (a sword); bend, weave, knit, join together; change color, vary; scheme, feign, pretend" (class III strong verb, past tense brægd, past participle brogden), from Proto-Germanic *bregthan "make sudden jerky movements from side to side" (cf. Old Norse bregða "to brandish, turn about, braid;" Old Saxon bregdan "to weave;" Dutch breien "to knit;" Old High German brettan "to draw, weave, braid"), from PIE root *bherek- "to gleam, flash" (cf. Sanskrit bhrasate "flames, blazes, shines"). In English the verb survives only in the narrow definition of "plait hair." Related: Braided; braiding.
in part from stem found in Old English gebrægd "craft, fraud," gebregd "commotion," Old Norse bragð "deed, trick," and in part from or influenced by related braid (v.). Earliest senses are "a deceit, stratagem, trick" (c.1200), "sudden or quick movement" (c.1300); meaning "anything plaited or entwined" (especially hair) is from 1520s.