Notation also allows us to speak generically about certain geometrical qualities of the board. Here are a few common examples.
Ranks and files are the correct technical terms for the rows and columns. We speak of the 1st rank and the a-file rather than the 1st row or the a-column.
The center consists of the four squares d4, d5, e4, and e5. Some writers speak of an 'extended center', which is the 4x4 square having c3 at the lower left and f6 at the upper right. In any case, the other squares are not considered to be part of the center.
The Queenside and Kingside are the halves of the board to the left and the right, again from White's point of view. The names correspond to the initial positions of the Queen and the King. Similarly, the White side and Black side are the lower and upper halves of the board facing each player.
The diagonals are often referred to by their starting and ending squares, from left to right. The 'a1 to h8' and 'a8 to h1' diagonals are the longest on the board, eight squares each.
