summerus
Could not find submerum in Logeion dictionaries.
submerum neuter nominative singular, neuter accusative singular, neuter genitive plural, neuter vocative singular, masculine genitive plural, masculine accusative singular of summerus
sum-mĕrus (subm-), a, um, adj.,
- rather pure: vinum, Plaut. Stich. 1, 3, 116 (270).