Why is the ninth month called September?
c.1200, "to stretch out, to send in various directions," probably from Old English -sprædan (especially in tosprædan "to spread out," and gesprædung "spreading"), from Proto-Germanic *spraidijanan (cf. Danish sprede, Old Swedish spreda, Middle Dutch spreiden, Old High German and German spreiten "to spread"), probably from PIE *sper- "to strew" (see sprout (v.)). Reflexive sense of "to extend, expand" is attested from mid-14c.
1690s, "extent or expanse of something," from spread (v.). Meaning "copious meal" dates from 1822; sense of "food for spreading" (butter, jam, etc.) is from 1812. Sense of "bed cover" is recorded from 1848, originally American English. Meaning "degree of variation" is attested from 1929. Meaning "ranch for raising cattle" is attested from 1927.