Penetration is the medical term for the penis entering into the vagina. It's a good way term for talking about sex if one wants to seem mature. Even if you're a dirty little pervert, you'll sound like sex is more than just an emotionless action caused by hormones if you call it 'penetration' rather than 'fucking around,' 'doing it,' etc.
Dude 1: Did you fucked your girlfriend last night?

Dude 2: Penetration occured and I depostited my semen inside of her vagina.

Dude 1: What the fuck? You're a frat boy, you don't talk like that.

Dude 2: I know, but I sure sound mature, don't I?
by Tit For Twat January 27, 2007
Get the penetration mug.
1. An object going through something with force.
The woman moaned as the penis slid into her vagina.
by Anonymous June 4, 2003
Get the Penetrating mug.
1. A word used to describe sex situation .
As in very deep into her.
2. Go through something. As in getting shot through.
1. He is so good! He is a penetration master!
2. These bullets are .44 , thus it can penetrate a wall. Be careful with them.
by Jesus with a Shotgun May 13, 2018
Get the Penetration mug.
The entering of one object into another, usually through some sort of semi-permeable membrane/skin/defense/covering.

See also:
1. Sexual penetration
2. Warfare penetration
3. Market penetration
4. Basketball penetration
5. Magical penetration
The addict will sometimes penetrate his arm with a syringe to inject drugs directly into his blood stream. This method of delivery is said to produce a more efficient high.
by Erinski Easy December 11, 2008
Get the penetrate mug.
In sex the disappearence of the penis into the vaginal cavity and the rupturing the hymen.
Kiersten's examination in the ER showed that the source of her vaginal bleeding was penetration and the puncturing of the back wall of her vagina as the source of the blood. Kiersten spoke of falling on her bicycle handlebar, but the experienced personnel in the ER knew rape when they saw it. Who was the rider of the second bike that was found? Someone said Kiersten had been seen riding with Peter Goesinya.
by Richard Black March 25, 2005
Get the penetration mug.
You get a good fuck when you penetrate.
It is much better than the woman giving you a hand job.
The sexspecialist grips tightly when I penetrate her
by St. Ias October 19, 2005
Get the penetrate mug.