microspore🔊nounEtymology From micro- + spore.1Biology, Botany, Natural sciences The smaller spore of a heterosporous plant, typically producing a male gametophyte.2Biology, Natural sciences, Zoology One of the numerous tiny spore-like elements produced through the encystment and subdivision of many monads.Derived termsmicrosporic, microsporogenesisRelated termsmegaspore, mesospore