phy·la (f??l?)n. Plural of phylum.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.phyla (?fa?l?) n (Linguistics) the plural of phylumCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014phy?lum (?fa? l?m) n., pl. -la (-l?). 1. the primary subdivision of a taxonomic kingdom, grouping together all classes of organisms that have the same body plan. 2. a category consisting of language stocks that, because of cognates in vocabulary, are considered likely to be related by common origin. [1875?80;