megaspore megasporangium • megasporic · · · Info · Definitions · Synonyms · Characters · · megaspore · · Text Latin · · Script 9 · · Length Definitions · · · (noun) larger of the two types of spore produced in heterosporous plants; develops in ovule into a female gametophyte. Synonyms: macrospore. · · Noun Definition 1 Synonyms · · · macrospore · · Synonym 1 Characters · · a latin small letter a U+0061 e latin small letter e U+0065 g latin small letter g U+0067 m latin small letter m U+006D o latin small letter o U+006F p latin small letter p U+0070 r latin small letter r U+0072 s latin small letter s U+0073