1590s, "to be consistent, to follow regularly in natural or logical order," from Latin cohaerere "to cleave together," in transferred use, "be coherent or consistent," from assimilated form of com "together" (see co-) + haerere "to adhere, stick" (see hesitation). More literal sense of "to stick, stick together, cleave" is from 1610s. Related: Cohered; cohering.
1550s, "harmonious;" 1570s, "sticking together," also "connected, consistent" (of speech, thought, etc.), from French cohérent (16c.), from Latin cohaerentem (nominative cohaerens), present participle of cohaerere "cohere," from assimilated form of com "together" (see co-) + haerere "to adhere, stick" (see hesitation).
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 *bindanan (source also of 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." Of books, from c. 1400. Intransitive sense of "stick together, cohere" is from 1670s.
mid-15c., cohercen, "restrain or constrain by force of law or authority," from Old French cohercier, from Latin coercere "to control, restrain, shut up together," from assimilated form of com- "together" (see co-) + arcere "to enclose, confine, contain, ward off," from PIE *ark- "to hold, contain, guard" (see arcane). The unetymological -h- was perhaps by influence of cohere. Related: Coerced; coercing. No record of the word between late 15c. and mid-17c.; its reappearance 1650s is perhaps a back-formation from coercion.