From StrategyWiki, the free strategy guide and walkthrough wiki

These are commonly-used terms in the world of Second Life. For more general terms, see Multiplayer/Glossary.

avatar 

A resident's physical representation in the virtual world.

rez 

A term taken from Tron, an object is 'rezzed' when it is spawned in-world.

Main Grid 

This is a massive network of simulators, accounting for the entire server. This could be compared to a world map.

simulator 

A simulator (or 'sim') is a piece of land owned by a resident (or a Linden) on which stores, objects, and other such things can be built. Essentially like a piece of land.

Furry 

n. pl. Furries A Furry is one whose avatar resembles an animal, such as a wolf or cat.

Gor 

A fictional world created by the author John Norman. Players have adopted settings from the world and created sims which are modelled after them. In SL, they strictly enforce RP.

OOC 

Out-Of-Character. 1. State of being where the speaker is speaking as themselves and not as a roleplayed character. 2. Referring to a behavior that is unlike that of the character being roleplayed.

IC 

In-Character. A state of being in which one is roleplaying as someone or something.

FL 

First Life. Referring to the real world outside of Second Life, and the internet in general.

SL 

Second Life. Referring to the world of Second Life or the game itself.