punctum
/ˈpʌŋktəm/noun
(pl. puncta /-tə/)
1- technical a small, distinct point〈技〉明显的小点。
1.1
- Anatomy the opening of a tear duct【剖】泪管口, 泪点。
词源
late 16th cent. （figuratively, denoting a point）： from Latin, literally 'a point'.