(1):

(n.) A spore provided with one or more slender cilia, by the vibration of which it swims in the water. Zoospores are produced by many green, and by some olive-brown, algae. In certain species they are divided into the larger macrozoospores and the smaller microzoospores. Called also sporozoid, and swarmspore.

(2):

(n.) See Swarmspore.