Onychomancy
Onychomancy (Greek onyx, nail) is divination by reading the patterns and marks on fingernails. Ancient practice: small white marks on the nails were interpreted as omens — popular European folkloric belief (each finger = different meaning).
Folkloric interpretations
White spots: thumb = wish; index = friend; middle = enemy; ring = letter; pinkie = travel. The reading is folkloric, without scientific basis.