Definition of mouse-pea in English:

mouse-pea

Pronunciation /ˈmaʊspiː/

noun

dialect Scottish, British
  • 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.