The portion or space of the coelom that extends outside the main body cavity, particularly in echinoderms and other marine animals.
From 'exo-' (outside) and 'coelom' (body cavity), a technical term combining Greek roots used in embryology and comparative anatomy since the 19th century.
A sea star's exocoelom is filled with seawater, not blood—they've essentially turned the ocean itself into part of their circulatory system, which is why they can only live in water.
Complete word intelligence in one call. Free tier — 50 lookups/day.