Some words that end with 'IN' are:
3 letter work beginning with ex
One living thing with 3 letters starting with e is an eel.
Trisect is a 7-letter word beginning with T. It means to cut into 3 parts.
Ate is the word.
amp
roe
The 3-letter answer to "had eaten" is almost always "ate." Check the "n."
TDs
tattle
Ado.
Jaw
A three letter word beginning with z has to be Zoo