n. [ Macro- + zoospore. ] (Bot.) A large motile spore having four vibratile cilia; -- found in certain green algae. [ 1913 Webster ]

n. [ Gr. w, 'o`n an egg + &unr_; a seed. ] (Bot.) (a) A special kind of spore resulting from the fertilization of an oosphere by antherozoids. (b) A fertilized oosphere in the ovule of a flowering plant. [ 1913 Webster ]

n. [ Zoo- + spore. ] [ 1913 Webster ]

1. (Bot.) 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. [ 1913 Webster ]

2. (Zool.) See Swarmspore. [ 1913 Webster ]