In phonetics, an abrupt sound made with the normal air stream, giving it an explosive character. The English sounds of P T K B D G are plosives (G as in go). All languages of the world have plosives.

In full, a plosive is a pulmonic egressive obstruent stop. Each of these terms contrasts with other possibilities. Pulmonic means the air is controlled by the lungs, and egressive means the direction is outward: almost all speech sounds are pulmonic egressive, but for those that aren't, see implosive, ejective, and click. None of those alternatives exist in English or in familiar European languages.

A stop has the mouth fully blocked at some point (lips for P B, gum ridge for T D, soft palate for K G). Often, when dealing with familiar languages where the difference isn't important, stop and plosive are used interchangeably. However, strictly the nasal consonants such as N and M are stops too, with resonance released through the nose. So plosives are obstruent stops, while nasals are resonant stops.

A plosive followed by a fricative segment, the whole occupying the duration of a single consonant and being treated as one by the phonology of a language, is called an affricate. English examples are CH (as in church) and J. Typically, the affricates pattern like the plosives, so P T CH K form a natural group.