centerfold

Short definition from Wiktionary

Noun

1. 1
   The single larger sheet of paper that forms the middle two pages of a magazine or other publication, folded so as to open wider than a standard page spread.
2. 2
   A large photograph printed on this sheet, typically in the form of a nude, or provocatively dressed, sexually attractive woman or man.
3. 3
   The person appearing in such a photograph.
4. 4
   Any very sexually attractive person, who is therefore material for such a photograph.