Sinum is a genus of predatory sea snails, marine gastropod mollusks in the subfamily Sininae of the family Naticidae, the moon snails.

[1] Most naticids have shells that are globular, but the shell of species in the genus Sinum is flattened to some extent, some being so flattened that they are ear-shaped.

This marine species is cosmopolitan.

Species within the genus Sinum include: The Indo-Pacific Molluscan database also mentions the following species with names in current use[11]