Definition of endcap:
(n) :
A product display at the end of a supermarket aisle
(n) :
A cap placed on the end of something.
(v) :
To add an endcap to.
(n) :
(television) A logo or visual sequence immediately following a programme, identifying the broadcaster or production company.
(v) :
(organic chemistry) To modify a reactive end of a polymer, typically by adding a trimethylsilyl group to a hydroxyl.