I seen

A phrase used by people speaking one of many dialects of the Midwest, meaning "I have seen" or "I saw".

I seen you borrow him a quarter so he could get a pop when he could have gone to the bubbler for free.
means
I saw you lend him a quarter so he could get a soda when he could have used the water fountain for free.

Seen Been

An alternative way to pronounce Sean Bean's name.

Person 1: Hey! Have you seen that scene in Game of Thrones with Seen Been?
Person 2: You mean Shawn Bawn? Yes, he's great!

Big Seen

when your crush seen zones your text

He's not looking so well.either he's sick or got the big seen today

seen peents

ya mean

sometimes followed by Friggin

peen peen peen. Seen Peents!?

sex seen

When you accidentally observe two people having sex that you really didn't want to.

I walked in on my grandparents doing it last night; that is definitely a sex seen I could've done without!

oh seen

A daft phrase used by Riaz in order to communicate when something has been understood.

ME "Hey Riaz, I heard you shoved a carrot up yo' ass"
RIAZ "Er, yeah"
ME "I got a pic of you doing it"
RIAZ "Oh, seen"

I seen it!

a phrase you might expect to say after seeing a girls foof or perhaps a boob or two

"hey peter, I seen it!"