A dabbaba (or dabaaba, dabbabah) is a fairy chess piece that jumps two squares orthogonally (the directions a chess rook can move), leaping over any intermediate piece. Below, it is given the symbol D.
The dabbaba is a very old piece, appearing in some very early chess variants, such as Tamerlane chess.
The name dabbaba (Arabic: دَبَّابَة) means tank in Modern Arabic. In older Arabic, it referred to a type of medieval siege engine designed to shelter men who are digging a hole in enemy fortifications (Latin vinea). The name has sometimes been translated as war engine. The name dabbaba was also used for other pieces in old chess variants, such as one that moved like the modern bishop.
The dabbaba by itself is not much more powerful than a pawn, but as an additional power to other pieces it is worth about half a knight. Four dabbabas (each covering a different quarter of the chessboard) and a king can easily force checkmate on a bare king. Its value as a piece by itself is severely compromised by its being "twice-colourbound", only being able to reach a quarter of the squares on the 8x8 chessboard; combining it with other pieces usually masks this weakness to some extent.