Dictionary.net

• White-fleshed lake fish of salmon kind. [Welsh]

1919 - The concise Oxford dictionary of current English
By Sir Augustus Henry

• [Welsh.] (Ichth.) Schelly, fresh-water herring, like the herring. Spec, of Coregonus, fam. Salmonidae, ord. Physostomi, sub-class Teleostei.

1895 - Glossary of terms and phrases
By Henry Percy Smith