Old English þider "to or toward that place," altered (by influence of its opposite hider) from earlier þæder "to that place," from Proto-Germanic *thadra- (cognates: Old Norse þaðra "there," Gothic þaþro "thence"), from PIE pronomial root *to- (see that) + PIE suffix denoting motion toward (compare Gothic -dre, Sanskrit -tra). The medial -th- developed early 14c. but was rare before early 16c. (compare gather, murder, burden).