Etymology: Common Germanic: Old English wǽpen neuter = Old Frisian wêpin, Old Saxon wâpan (Middle Low German wâpen, whence Middle High German wâpen, wâppen, modern German wappen only in the sense of armorial bearings), Old High German wâfan (Middle High German wâfen neuter, modern German waffe feminine), Old Norse vápn neuter (Swedish vapen, Danish vaaben), Gothic *wēpn (plural wēpna) < Old Germanic *wǣpno-m < pre-Germanic *wēbno-m. A parallel type *wǣƀno-m ( < pre-Germanic *wēpnó-m) is supposed by some scholars to be implied by certain rare forms in various Germanic languages: Old High German or Old Saxon ( Hildebrandslied) wâbnum dative plural, Old English wǽmn, Old Norse vámn. Outside Germanic no probable cognates have been found.The northern Middle English wāpen (later wappen ) and the rare (East Anglian) wopen represent the Old Norse vápn : compare wapentake n., wappenschaw n. The shortening of the long stressed vowel in the first syllable is normal; Ormin has still the Old English quantity. The plural in Old English was normally identical in form with the singular, but in the 10th- and 11th-century forms with final -u occur. In Layamon c1205 the plural is usually wepnen , though there are also examples of wepne and wapen . From the beginning of the 14th cent. the plural has in ordinary use been formed with the suffix -(e)s ; with regard to the occasional uninflected plural see 1b below.

Etymology: Old English wǽpnian , < wǽpen weapon n.; compare Old High German wâffanen, -ôn (Middle High German wafenen, wæfenen, modern German waffnen), also Middle High German wapenen (modern German wappnen, to clothe in armour), Old Norse vápna.