Meaning

noun a tropical tree or shrub bearing fruit that germinates while still on the tree and having numerous prop roots that eventually form an impenetrable mass and are important in land building

originA modification of earlier mangrowe (obsolete) by the influence of grove (“small forest”) through folk etymology. Mangrowe is probably borrowed from Spanish mangle, mangue (whence English mangle) (probably from an Arawak language (such as Taíno), or a Cariban language) + an unknown word ending.

Etymology from Wiktionary, CC BY-SA 3.0