sleeve tattoo (or tattoo sleeve) is a large tattoo, or a collection of smaller tattoos, that has a unified theme, that covers most or all of a person's arm, 
What'd a sleeve tattoo?
sleeve tattoo has a unified theme, whereas an arm covered in tattoos may have many tattoos 
OK why he need for tattoo in the first place?
Tattooing has been practiced across the globe since at least Neolithic times, as evidenced by mummified preserved skin, ancient art
Wow! It really dates back!
sleeve" is a reference to the tattoo's size similarity in coverage to a long shirt sleeve on an article of clothing
So now do one remove tattoo?
Tattoo removal
Tattoo removal has been performed with various tools since the start of tattooing. While tattoos were once considered permanent, it is now possible to remove them with treatments, fully or partially.
The "standard modality for tattoo removal" is the non-invasive removal of tattoo pigments using Q-switched lasers. Different types of Q-switched lasers are used to target different colors of tattoo ink depending on the specific light absorption spectra of the tattoo pigments. 
Typically, black and other darker-colored inks
Sleeve tattoo
A sleeve tattoo (or tattoo sleeve) is a large tattoo, or a collection of smaller tattoos, that has a unified theme, that covers most or all of a person's arm, usually from shoulder to wrist.
There is a difference between an arm covered in tattoos and a sleeve tattoo. A sleeve tattoo has a unified theme, whereas an arm covered in tattoos may have many tattoos of different styles that does not have an overall unity.
The term "sleeve" is a reference