se·pal (s??p?l)n. One of the usually green leaflike structures composing the outermost part of a flower. Sepals often enclose and protect the bud and may remain after the fruit forms.[New Latin sepalum, perhaps blend of Greek skep?, covering and Latin petalum, petal; see petal.]sep?a·line (s?p??-l?n), sep?a·lous (-l?s) adj.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.sepal (?s?p?l) n (Botany) any of the separate parts of the calyx of a flower[C19: from New Latin sepalum: sep-, from Greek skep? a covering + -alum, from New Latin petalum petal] ?sepalled, sepalous adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014se?pal (?si p?l) n. one of the individual leaves or parts of the calyx of a flower. [