From Second Life Wiki
Scripts are items placed in an objects inventory (marked with the icon) to create an effect. This effect has a very large number of things that it can do. How objects look, move, interact with avatars, and communicate are all examples of what can be done with scripts.
Scripts are created through an in-world editor similar to a text file editor. Key words that perform specific actions or run when an action is performed are highlighted. The language used to write scripts is Linden Scripting Language (LSL), and is an event oriented programming language.
This category is for functions and events that are connected with the script Virtual Machine (VM), the functions control or query the VM and the events are some aspect of the result of that interaction. For functions and events who's functionalities are specific to scripts and in there nature.
Sharing Script Access
In the course of shared projects, you may often need to let team members access scripts in objects owned by you, or need yourself to access scripts in objects owned by them.
To enable this, see: Editing someone else's scripts and notecards.