While I was researching fetal alcohol syndrome characteristics for a caregiver, I ran across this really interesting chart showing "typical" facial features of individuals with Fetal Alcohol Spectrum Disorder. One facial feature in particular, the philtrum, is given a lot of attention.
Not too long ago someone told me my son looks like just me. They mentioned my eyes and pointed to my lips and said "That thing above your lip. His looks like that too." Neither of us could think of what the part of the face is called, so imagine my surprise when that earlier reference question led me just to the word I forgot I needed: philtrum.
Why do we have a philtrum? Dr. David Moseley in this clip, explains “It is the place where the puzzle that is the human face finally all comes together". http://www.iflscience.com/health-and-medicine/why-do-we-have-little-groove-under-our-nose