noun

1. The act or quality of endorsing

   “Companies sometimes pay millions for product endorsement by celebrities.”

2. An amendment or annotation to an insurance contract or other official document (such as a driving licence).

   “Mr. Jones paid extra for the flood damage endorsement on his house insurance.”

3. An instructor's signed acknowledgement of time practising specific flying skills.

   “Once she obtained the endorsement of her night flying hours, Joanna was approved to take the pilot's examination.”