pod (n.1)
"seed of beans," 1680s, of uncertain origin; found earlier in podware "seed of legumes, seed grain" (mid-15c.), which had a parallel form codware "husked or seeded plants" (late 14c.), related to cod "husk of seeded plants," which was in Old English. In reference to pregnancy from 1890; in reference to a round belly from 1825. Meaning "detachable body of an aircraft" is from 1950. Pod people (1956) is from movie "Invasion of the Body Snatchers," based on novel by Jack Finney.
pod (n.2)
"herd of whales or seals," 1827, American English, of unknown origin.