Old English glidan "move along smoothly and easily; glide away, vanish; slip, slide" (class I strong verb, past tense glad, past participle gliden), from Proto-Germanic *glidan "to glide" (source also of Old Saxon glidan, Old Frisian glida, Old High German glitan, German gleiten), probably part of the large group of Germanic words in gl- involving notions of "smooth; shining; joyful," from PIE root *ghel- (2) "to shine." Related: Glided; gliding. Strong past tense form glid persisted into 20c.