look up any word, like dirty sanchez:
 
2.
The groove in the upper lip
A philtrum; what my FAS friend lacks
by Eviscerati December 09, 2008
 
1.
The two lines and the dent formed by them, under ones nose extending to the top of the upper lip.

Son of a Bitch!! That coffee just burned the shit out of my philtrum.
by Richard Kirshen October 28, 2003
 
3.
The word philtrum has 2 main meanings:
1: noun. The little groove between the bottom of your nose and your top lip. I have no clue what it is there for, but now you know what it is called.
2: verb. The art of performing oral sex while shaving. This originated because some kid at my school with a dirty mind thought it was 'full trim'. The term has since caught on and is now widely recognised.
1: You:"hi Steph! How you been?
Steph:"philtrum" *pokes your philtrum. walks away*

2: You:"hey sweety!"
Boyfriend:"her my giiiirl. Guess what I learnt today?"
You:"what?"
Boyfriend:"how to philtrum"
by *Angela lolly* February 20, 2013