Although modern Breton has lost its ancestral dual number marker, relics of its use are preserved in various nouns pertaining to body parts, including the words for eyes, ears, cheeks, legs, armpits, arms, hands, knees, thighs, and wings. This is seen in a prefix (formed in , or ) that is etymologically derived from the prefixation of the number two. The dual is no longer productive, and has merely been lexicalized in these cases rather than remaining a part of Breton grammar. The (etymologically) already dual words for eyes () and ears () can be pluralized "again" to form and .