Some of the possible meanings of “tn” are:
Tennessee: TN is the two-letter abbreviation for the U.S. state of Tennessee. However, it is unlikely that “tn” would be used to refer to this state in a text of 800 words, as there would be no reason to abbreviate it.
Turn: “tn” could be a shorthand for “turn” in certain contexts, such as gaming or sports. For example, someone might write “It’s your tn” to mean “It’s your turn” in a game.
Thanks: “tn” could also be a shortened version of “thanks” in some texting shorthand. For example, someone might write “tnx” to mean “thanks” in a text message.
Tiny: “tn” could also refer to “tiny” in some contexts where space is limited, such as on Twitter or in a text message. For example, someone might write “That dog is so tn!” to mean “That dog is so tiny!”