noun Etymology: model 16 Date: 1968 a .223 caliber (5.56 millimeter) gas-operated magazine-fed rifle for semiautomatic or automatic operation used by United States troops since the mid 1960s
M16
Meaning of M16 in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012