A·li (ä-l??) Full name Ali ibn Abi Talib. 600?-661. Muslim caliph (656-661) whose reign was marked by the division of Islam into Sunni and Shiite sects. This schism intensified after his assassination by members of a third Muslim sect.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.Ali (???li?) n1. (Biography) ?600?661 ad, fourth caliph of Islam (656?61 ad), considered the first caliph by the Shiites: cousin and son-in-law of Mohammed2. (Biography) See Mehemet Ali3. (Biography) See Muhammad AliCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014A?li (?? li, ??li for 1?4; ??li for 5 ) n. 1. (?Al? ibn-abu-Talib), a.d. c600-61, fourth caliph of Islam 656-661 (cousin and son-in-law of Muhammad): considered the first caliph by Shi?ites. 2. Muhammad (Cassius Marcellus Clay, Jr.), born 1942, U.S. boxer. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.