Emily Dickinson Lexicon

FRITH, n. [L. fretum; Gr. πορθμος, from πειρω, to pass over, or πορευω, πορευομαι, to pass; properly, a passage, a narrow channel that is passable or passed.]

1. A narrow passage of the sea; a strait. It is used for the opening of a river into the sea; as, the frith of Forth, or of Clyde.
2. A kind of wear for catching fish. Carew.