Why is the ninth month called September?
Old English glidan "move along smoothly and easily, glide, slip, slide" (class I strong verb, past tense glad, past participle gliden), from West Germanic *glidan "to glide" (cf. Old Saxon glidan, Old Frisian glida, German gleiten). Related: Glided; gliding. Strong past tense form glid persisted into 20c. The noun is attested 1580s, from the verb.