1610s, from Latin uterus "womb, belly" (plural uteri), from PIE root *udero- "abdomen, womb, stomach" (cf. Sanskrit udaram "belly," Greek hystera "womb," Lithuanian vederas "sausage, intestines, stomach, lower abdomen," Old Church Slavonic vedro "bucket, barrel," Russian vedro), perhaps originally in PIE "outer, sticking out," shifting to "belly" via "protruding."