3 named features carry the IAU descriptor Mare — a large dark plain — an ancient lava flood, not a sea on Titan, out of 25 in the mapped Solar System.
The IAU assigns each feature class on each world a naming theme. Across the 3 maria with a recorded origin, 3 categories appear, led by Norway.
Every one has its own page, on the surface it sits on.
The same descriptor is used on 1 other world, for 22 more features.