checker

1. One who checks or verifies something.
2. One who makes a check mark.
3. The clerk who tallies cost of purchases and accepts payment.

   There was a long line at the grocery store because the checker was so slow.

4. One who hinders or stops something.

1. A playing piece in the game of checkers (British: draughts).
2. A pattern of alternating colours as on a chessboard.

1. To mark in a pattern of alternating light and dark positions, like a checkerboard.
2. To develop markings in a pattern of alternating light and dark positions, like a checkerboard.

noun

The fruit of the wild service tree or chequer tree, Photinia villosa, syn. Sorbus terminalis