In phonetics, a stop, also known as a plosive, is an oral occlusive, a consonant in which the vocal tract is blocked so that all airflow ceases. The occlusion may be done with the tongue (blade [t], [d], or body [k], [ɡ]), lips ([b], [p]), or glottis ([ʔ]). Stops contrast with nasals, where the vocal tract is blocked but airflow continues through the nose, as in /m/ and /n/, and with fricatives, where partial occlusion impedes but does not block airflow in the vocal tract.

The terms stop, occlusive, and plosive are often used interchangeably. Linguists which distinguish them may not agree on the distinction being made. The terms refer to different features of the consonant. "Stop" refers to the airflow which is stopped. "Occlusive" refers to the articulation, which occludes (blocks) the vocal tract. And "plosive" refers to the release burst (plosion) of the consonant.

Either "occlusive" or "stop" may be used as a general term covering the other together with nasals. That is, 'occlusive' may be defined as oral occlusives (stops/plosives) plus nasal occlusives (nasals such as [m], [n]), or 'stop' may be defined as oral stops (plosives) plus nasal stops (nasals). Ladefoged and Maddieson (1996) prefer to restrict 'stop' to oral occlusives. They say,