Entry 1 sense Webster, 1913 Presidio /prĭs-ĭd'-ē-ōˌ/ · Pre·si·di·o · IPA /prɪsˈɪdiːˌoʊ/ 01 n. A place of defense; a fortress; a garrison; a fortress; a garrison or guardhouse. 1. A place of defense; a fortress; a garrison; a fortress; a garrison or guardhouse.