pearl: [14] Latin perna originally signified ‘leg’, and hence ‘ham’. It came to be applied metaphorically to a variety of sea-mussel whose stalk-like foot resembled a ham in shape. Such mussels could contain pearls, and so a diminutive form *pernula seems to have been coined in Vulgar Latin to designate ‘pearl’. This was later contracted to *perla, which passed into English via Old French perle.
