Filtrum vs. Philtrum — What's the Difference?

Alternative spelling of philtrum

The philtrum (Latin: philtrum from Ancient Greek φίλτρον phíltron, lit. "love charm"), or medial cleft, is a vertical indentation in the middle area of the upper lip, common to many mammals, extending in humans from the nasal septum to the tubercle of the upper lip.

In humans and certain other primates, the vertical indentation in the center of the upper lip.

In many other mammals, the cleft running through the center of the upper lip and often between the nostrils.

(anatomy) The shallow vertical groove running from the nasal septum to the center of the upper lip.

(zootomy) The junction between the two halves of an animal's upper lip or nose.