"40 mike-mike" describes any weapon firing a 40mm grenade. Heard in rap lyrics, drill music, video-game chat or street-style social media, it is more often quoted than acted on. What matters is context: are they repeating a song line, or are they describing specific people, places and plans? If the language pairs with secrecy, sudden new friends, or worry about someone they know, that is the cue for a calm direct conversation, ideally before involving anyone else.
40 mike-mike
(US, _, Army, and, Marines, military, slang) Any weapon firing a 40mm grenade.
Etymology timeline
Born ~1970 · no dated citations yetBoomer / counterculture eraSee decade cohort →
Definitions
Global
#1·Apr 26, 2026Global
(US, _, Army, and, Marines, military, slang) Any weapon firing a 40mm grenade. Often specifically the M203 grenade launcher, mounted underneath an M-16 or its variant. In the Marine Corps, often the Mark-19 Automatic 40mm Grenade Launcher.
Origin: From the letter M in the ICAO spelling alphabet. Origin information sourced from Wiktionary contributors (CC BY-SA 4.0).
For parents
"40 mike-mike" describes any weapon firing a 40mm grenade. Heard in rap lyrics, drill music, video-game chat or street-style social media, it is more often quoted than acted on. What matters is context: are they repeating a song line, or are they describing specific people, places and plans? If the language pairs with secrecy, sudden new friends, or worry about someone they know, that is the cue for a calm direct conversation, ideally before involving anyone else.
For ESL learners
"40 mike-mike" is informal English meaning any weapon firing a 40mm grenade. It is mainly used in North American English. A more formal or neutral equivalent would be something like "any weapon firing a 40mm grenade" expressed in standard vocabulary. A common mistake is to assume "40 mike-mike" can replace its standard equivalent in every register; keep it for spoken or casual situations and use the formal form in writing. If you are a B2 or C1 learner, it is useful to recognise this word when you hear or read it, but think carefully about whether the situation really calls for it before using it yourself.
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For specific readers
Why is this section here?
Slang is read by different audiences for very different reasons. The For parents view re-explains the term in plain, non-judgemental language so a caregiver can understand what their child means without needing the surrounding subculture. The For English learners view focuses on register (when it's safe to use), formal alternatives, and common mistakes — what a textbook won't teach you.
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Regional slang from around the English-speaking world — British, Australian, Irish, Caribbean, Nigerian, Filipino, AAVE, and the hyphenated-English dialects that make the internet sound local.
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