noun. A small hook for fastening a button on shoes or gloves.

noun. A pass pattern in which the receiver runs straight downfield and then turns abruptly back toward the line of scrimmage to catch the ball.

noun. A hook used to pull thread through the holes of a button

noun. A play in which the receiver runs straight downfield, then turns back toward the line of scrimmage

"As they reached the end of the line, they slowly filed past one or more PHS officers who, at a glance, surveyed them for a variety of serious and minor diseases and conditions, finally turning back their eyelids with their fingers or a buttonhook to check for trachoma."