<p><strong>Noun</strong></p><ul><li>a submarine.</li><li>a substitute: We've got a sub in English this week because our teacher's home with the flu.</li><li>a submarine sandwich.</li><li>a submissive in a BDSM sexual encounter or relationship.</li><li>a subcontractor.</li><li>a sublieutenant.</li><li>a subordinate.</li><li>a subaltern.</li><li>British. an advance against one's wages, especially one granted as a subsistence allowance.</li><li>Photography. a substratum.</li></ul><p><strong>Verb</strong></p><ul><li>(used without object), subbed, sub·bing: to act as a substitute for another.</li><li>to act as the submissive partner in a BDSM sexual encounter or relationship.</li><li>(used with object), subbed, sub·bing: Photography. to coat (a film or plate) with a substratum.</li></ul>