na·ta·to·ri·al (nā'tə-tôr'ē-əl, -tōr'-, nāt'ə-) adj. Of, relating to, adapted for, or characterized by swimming: a natatorial appendage; natatorial birds.
[From Late Latin natātōrius, from Latin natātor, swimmer, from natātus, past participle of natāre, frequentative of nāre, to swim; see snā- in Indo-European roots.]