mouse-pea
/ˈmaʊspiː/Now Scottish and English regional (northern )
noun
Any of various kinds of wild vetch, especially bitter vetch, Lathyrus linifolius, and tufted vetch, Vicia cracca. Also: the fruit of such a vetch.
Origin
Old English; earliest use found in Antwerp Glossary. From mouse (or occasionally its plural mice) + pease; in later use in some forms the second element was probably apprehended as plural. In some forms a re-formation from mouse + pea. In some forms from the genitive of mouse + the plural of pea; compare the parallel formation represented by Scots mousie's pea.