It is a "Chess engine" or program that tells you what moves to make in a given situation. If you are not using one (which the post seems to indicate that you are not) then you don't need to worry about it.
engines

Hi, I've been playing on this site for a couple of months but am just now advancing a little. I was just accused of using an engine by someone that i was playing and when I asked my opponent what that was, he just posted lol a bunch and said that he doesnt play with cheaters. What is an engine and is that something I should be worried about on this site. Thank you
Basically, he accused you of using a computer program to play the game. IE, he makes his move, you then play his move in Chessmaster or Rybka, the computer then makes a move, you play the computers move against your friend- that kind of thing(or other inappropriate use of software). Using a chess engine in such a way is against Chess.com policy and can get you banned. We play here to play with other players- if we wanted to play with Rybka, we would download Rybka and play it(No, I do not think you used an engine and am not accusing, I am just trying to explain clearly and directly what this person has accused you of).

Hi, I've been playing on this site for a couple of months but am just now advancing a little. I was just accused of using an engine by someone that i was playing and when I asked my opponent what that was, he just posted lol a bunch and said that he doesnt play with cheaters. What is an engine and is that something I should be worried about on this site. Thank you
P.S. What you have described sounds like the talk of a sore loser. The appropriate response to his claim would be "How would you know if I am using an engine". (Chess.com has ways of determining if people have been using them- I doubt the typical player does however)

P.S. What you have described sounds like the talk of a sore loser. The appropriate response to his claim would be "How would you know if I am using an engine". (Chess.com has ways of determining if people have been using them- I doubt the typical player does however)
I think the appropriate response is clicking disable chat right away.
Hi, I've been playing on this site for a couple of months but am just now advancing a little. I was just accused of using an engine by someone that i was playing and when I asked my opponent what that was, he just posted lol a bunch and said that he doesnt play with cheaters. What is an engine and is that something I should be worried about on this site. Thank you