San An·to·ni·o (s?n ?n-t??n?-??) A city of south-central Texas southwest of Austin on the San Antonio River, flowing about 320 km (200 mi) southeast to San Antonio Bay on the Gulf of Mexico. The city was founded as a Franciscan mission in 1718 and is the site of the Alamo, which was besieged and captured by Mexican forces in February-March 1836. It has several military bases.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.San Antonio (sæn æn?t??n????) n (Placename) a city in S Texas: site of the Alamo; the leading town in Texas until about 1930. Pop: 1 214 725 (2003 est)Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014San An?to?ni?o (?sæn æn?to? ni?o?) n. a city in S Texas: site of the Alamo. 1,067,816. San` An?to?ni?an, n., adj. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.