Define prone . prone synonyms, prone pronunciation, prone translation, English dictionary definition of prone . adj. 1. Lying with the front or face downward. 2. Having a tendency; inclined. Often used in combination: paper that is prone to yellowing; an... PRONE definition: 1. likely to show a particular characteristic, usually a negative one, or to be affected by…. Learn more. Master the word " PRONE " in English: definitions, translations, synonyms, pronunciations, examples, and grammar insights - all in one complete resource. In this first video, Kathleen Vollman demonstrates who and when to prone safely, as well as the best proning methods to use with mobility teams. She discusse...