cobra (n.) Look up cobra at
1802, short for cobra capello (1670s), from Portuguese cobra de capello "serpent (of the hood)," from Latin colubra "a snake, female serpent" (source of French couleuvre "adder"), which is of uncertain origin. So called for the expandable loose skin about its neck. The word came to English via Portuguese colonies in India, where the native name is nag (see naga).