Picture of Lentigo
Lentigo: A type of freckle that is a small tan, brown, or black spot which tends to be darker than the usual (ephelis-type) freckle and which do not fade in the winter. This kind of spot is referred to as lentigo simplex. Although lentigines may be part of a genetic disorder, for the most part they are just isolated and unimportant spots. (The genetic disorder in which lentigines occur is called the LEOPARD syndrome.)
Lentigo is the Latin word for lentil. A lentigo looks like a lentil bean. The plural is lentigines.
Source: MedTerms™ Medical Dictionary by MedicineNet, Inc.