lentigo
Concise Oxford English Dictionary © 2008 Oxford University Press:
lentigo /lɛnˈtʌɪgəʊ/
▶noun (pl. lentigines /-ˈtɪdʒɪniːz/) a condition marked by small brown patches on the skin.
– origin ME: from L., from lens, lent- ‘lentil’.
'lentigo' also found in these Oxford entries:

