Old English bindan "to tie up with bonds" (literally and figuratively), also "to make captive; to cover with dressings and bandages" (class III strong verb; past tense band, past participle bunden), from Proto-Germanic *bindan (cf. Old Saxon bindan, Old Norse and Old Frisian binda, Old High German binten "to bind," German binden, Gothic bindan), from PIE root *bhendh- "to bind" (see bend). Intransitive sense of "stick together" is from 1670s. Of books, from c.1400.