tattoo sleeve
A sleeve tattoo or tattoo sleeve is a large tattoo or collection of smaller, usually connected tattoos that covers most or all of a person's arm or leg. While a 'full' sleeve will cover the entire arm from shoulder to wrist or entire leg from groin to ankle, there are also 'half' and 'quarter' sleeves which cover less, but will still typically envelop the entire arm just as a garment would.
This tag implicates tattoo (learn more).