Philtrum

Part of speech: noun

Pronunciation: /ˈfɪl.tɹəm/

Definitions

1. The anatomical groove found in the center of the upper lip delineates the space between the nose and lip in humans
2. This central vertical line on the upper lip serves to separate the nose from the lip area, contributing to facial aesthetics
3. The narrow indentation located in the middle of the upper lip distinguishes the nasal region from the lip and plays a role in facial symmetry

Etymology: The groove running from the nose to the upper lip has a name that once belonged to a love potion. The Ancient Greek "phíltron" meant a love charm, and the same word was also used for the dimple in the upper lip, a link that makes the anatomical sense less random than it first appears. Latin took the word as "philtrum," and English borrowed it from there for the body part, while its sibling "philter," the magic drink itself, came into English along a separate path. The two words are doublets, meaning they descend from the same Greek source but arrived in English by different routes and took on different senses. Keeping them apart shows how one ancient word can split into a medical term for a facial feature and a term for enchantment.