The four centre squares e4, d4, e5 and d5. The area bounded by c3, c6, f3 and f6 is also considered central. The d and e files are the centre files. The centre of the board is of great strategic significance, as pieces placed there generally have the greatest scope.
CENTRE
Meaning of CENTRE in English
English glossary of chess terms. Английский глоссарий шахматных терминов. 2012