math

In what context is the capital T in?
If it is related to matrixes, it is in the top right corner to mean transpose.

This site has more info if this is what you're looking for:
https://www.khanacademy.org/math/algebra/algebra-matrices/Basic_matrix_operations/v/transpose-of-a-matrix

earhart:

what does a capital T stand for?

Kitty is right but it is commonly used for Temperature.
We'd have to see the question.