The letter 't' itself is a consonant in the English alphabet, and it typically represents a voiceless alveolar plosive sound. In various contexts, 't' can refer to several things, such as a variable in mathematics, a representation of time in physics, or even as an abbreviation in informal communication (e.g., 't' for 'time' or 'tea').
The letter 't' derives from the Latin letter 'T', which in turn was adapted from the Greek letter 'tau' (Τ, τ), and ultimately traces back to the Phoenician letter 'taw', which represented a cross or mark.
If you meant a different word, please clarify!