Definitions for to a t
to a T, to the letter, just right, to perfection(adverb)
in every detail
"the new house suited them to a T"
to a T(Adverb)
Precisely; exactly; perfectly; with great attention to detail.
Origin: The origins of this phrase are uncertain, but it has been observed in print since at least 1889, and likely was around well before that. The potentially related phrase "to a tittle" is found in a 1607 play, The Woman Hater by Francis Beaumont and John Fletcher ("I'll quote him to a tittle"). The T in the phrase to a T is likely the first letter of a word, with tittle being the most likely source.