'Pneumatophore' definitions:

Definition of 'pneumatophore'

noun

An air-filled root (submerged or exposed) that can function as a respiratory organ of a marsh or swamp plant

From: GCIDE

Pneumatophore \Pneu*mat"o*phore\, n. [Pneumato- + Gr. fe`rein to bear.] (Zool.) One of the Pneumonophora. [1913 Webster]