to a T (or tee) exactly; to perfection. informal

☞ This origin of this idiom, which dates back to the late 17th century, is uncertain. Attempts to link T with either a golfer's tee or a builder's T-square are unconvincing. It is possible that the underlying idea is that of completing the letter T by putting in the cross stroke, but the early 17th-century expression to a tittle was identical in meaning, and it is possible that T may be an abbreviation of tittle.

2000Post (Denver) He's got Ralphie's same non-charismatic charisma down to a T.