TPTK is short for "Top Pair Top Kicker". In French, we could say "meilleure paire avec meilleur acolyte". For example, if you have AK on 2-5-K-7-7, you have TPTK with the pair of kings kicked to the ace. The term TPTK is more commonly used in chat rooms. You'll see it in writing, but it's very rare that you'll hear someone say they had TPTK. You may also read it in some poker strategy books.
TPTK, TPFK, TPBK
We took the example above of AK over 2-5-K-7-7. The highest pair with the best sidekick is defined as TPTK. If we had KJ on the same board, we would have called our hand TPFK, which is Top Pair Fair Kicker. A hand like K6 on the same board (2-5-K-7-7) would have been defined as TPBK (Top Pair Bad Kicker). Generally, when there are only two of you after the flop, TPTK will be a very strong hand (unless you have had a lot of resistance from your opponent).