Playmate

Play′mateˊ

,

Noun.

A companion in diversions; a playfellow.

,

Noun.

A playfellow; a companion in diversions.

playmate ‎(plural playmates)

A companion for someone (especially a child) to play with.
- 1977, Agatha Christie, An Autobiography, Part I, chapter4:
  An indulgent playmate, Grannie would lay aside the long scratchy-looking letter she was writing (heavily crossed ‘to save notepaper’) and enter into the delightful pastime of ‘a chicken from Mr Whiteley's’.
A female who has appeared as the centerfold in Playboy magazine.

companion to play with

woman who has appeared in Playboy magazine