If something fits me to a tee, is it tee, t, or tea? I guessing it's tee from golf, but I don't really know.
Thanks!
"To a T" shows up earlier than "to a tee." But both have been around for centuries. "T" appears in the 1600s; the "tee" version about a century later. The origin is foggy.
Another thought: Maybe it's from drafting, and the t-square? If you measure an angle to make sure it's 90 degrees, and it fits perfectly, you could say it fits "to a t", dropping the "-square".
Best guess (t-square considered) is very likely it is a shortened version of an even older expression "to a tittle" with the same meaning. You may recognize "tittle" as a small mark in writing as in "jot or tittle."
I just found an excellent expert opinion on this in Michael Quinion and his website: