black-stem spleenwort blacks·temsp·leen·wort uncommon noun 1. fern of tropical America: from southern United States to West Indies and Mexico to Brazil Synonymsblack-stem spleenwortblack-stemmed spleenwortlittle ebony spleenwort Related words Broader terms spleenwort WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.