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1.
The simple diffusion of water (H20) into the plasma membrane. The diffusion of water is determined by the concentration of dissolved substances in the surrounding enviroment.
Osmosis is integral to life. A change in the surrounding enviroment could disrupte the homeostasis of a cell.
by JoshMiller March 21, 2004
 
2.
The transfer of something from an area with a high concentration of said thing to an area with a low concetration through a permeable membrane. A study method popular with many pupils and students, usually achieved by falling asleep with ones head directly atop of ones study materials.
Student #1: Dude, I'm soooo tired and stressed about tomorrow's test, I'm soooo unprepared.

Student #2: Dude, relax. You can kill 2 birds with 1 stone, just use osmosis.
by theboi December 23, 2009
 
3.
The net diffusion of water molecules across a semi-permeable plasma membrane
Imagine a tea bag, the bags walls are porous (holes in them) just like a membrane.

The water displaces inside the bag, now although this has a lot to do with environmental pressure (ie. the water) it is mostly to do with diffusion, Osmosis is a form of diffusion*, specifically across a semi - permeable (porous) membrane.

*

Diffusion is displacement of molecules so that they are equal.

E.g. Imagine your friend sprays deodorant/perfume on the far side of the room, it takes a couple of seconds to reach you.
It is a highly concentrated cloud at first but then spreads (diffuses) into the air until there are an EQUAL concentration of spray to the air.

E.g. five 1 pennies to every three 2 pennies
by Mantrastic February 05, 2010
 
4.
acquiring knowledge without actually seeking it
It was through osmosis that I learned about this blatantly undesirable video game.
by The Return of Light Joker April 05, 2011
 
5.
The first name to a man who's last name is Jones.
Bob: Hey, you see Osmosis?
Jane: Osmosis Jones? Yeah! I love that movie.
by James Yeehaw December 04, 2010
 
6.
The simple diffusion of water (H20) into the plasma membrane. The diffusion of water is determined by the concentration of dissolved substances in the surrounding enviroment. This is done through suckage.
"The plant's cells sucked the water in via Osmosis"
by BiologyPHD August 10, 2012
 
7.
an extremely funny word to laugh at
Person 1#: OSMOSIS!!!

Person 2#: HAHAHAHAH!
by unknown6989 December 23, 2008