What is an object in Scratch which performs functions controlled by scripts?

Explanation

The Scratch editor has three main parts : They are stage, Sprite and Script editor .
Stage :
(i) Stage is the background appearing when we open the scratch window
(ii) The background will most often be white. You can change the background colour as you like.
Sprite :
(iii) THe characters on the background of a scratch window are known as Sprite.
(iv) Usually a cat appears as a sprite when the Scratch window is opened .
(v) The software provides facilites to make alternations in sprite.
(vi) Script editor/costume editor : Where you edit your programs or your sprite's pictures.