- Accuracy: a score from 0 to 100 for how close your moves were to the engine’s best moves.
- Analysis board: a free board with an engine to try moves and see the best lines.
- Back-rank mate: checkmate on the first rank when the king is trapped behind its own pawns.
- Blunder: a very bad move that loses a lot (for example a piece or the game).
- Book move: a move that is known opening theory.
- Bullet, Blitz, Rapid, Classical: time categories, from the fastest to the slowest.
- Castling: a special move that tucks the king away and brings a rook into play.
- Check: the king is attacked. You must answer it.
- Checkmate: the king is attacked and there is no escape. The game is over.
- Course rating: a training rating you earn in courses.
- Deep review: a game review with a deeper search (depth 18).
- Developing: moving pieces off their starting squares toward the centre.
- Discovered attack: a piece moves and unmasks an attack by another piece behind it.
- Draw: the game ends in a tie (agreement, repetition, stalemate, fifty moves, insufficient material).
- Elo / rating: a number for playing strength. chessGM uses Glicko.
- En passant: a special pawn capture “in passing”.
- Endgame: the last phase of the game, with few pieces.
- Evaluation: the engine’s number for who is better, in pawns. +1.0 is about one pawn better for White.
- FEN: a text line that describes a position.
- Fork: one piece attacks two or more at once.
- Gambit: an opening that gives a pawn for an attack or lead in development.
- Increment: extra seconds added after each move.
- Key moment: a turning point in a game, shown in the review.
- Middlegame: the phase between the opening and the endgame.
- Opposition: a king-and-pawn idea: kings facing each other with one square between.
- Pin: a piece cannot move because a more valuable piece (or the king) is behind it.
- PGN: a text format for a whole game.
- Premove: a move you make in advance, played at once when it is your turn.
- Promotion: a pawn reaches the last rank and becomes a queen, rook, bishop or knight.
- Provisional rating: a rating shown with “?” because it is still settling.
- Repertoire: the openings you play as White and Black.
- Skewer: an attack on a valuable piece that must move, exposing a piece behind it.
- Spaced repetition: reviewing something just before you would forget it. The lines trainer does it for you.
- Stalemate: the player to move has no legal move but is not in check. It is a draw.
- Tempo: a move, or the time you gain by making a useful one.
- Zugzwang: every move makes your position worse, but you must move.
Open this in chessGM (opens in a new tab)
chessGM is not affiliated with Chess.com, Lichess or Stockfish; they are named only to say what the app can read or compare with.