semipostal
/ˌsɛmɪˈpoʊstəl/Definitions
1. adjective
Relating to or characteristic of a type of postage stamp that contributes a portion of its face value to a charity or cause.
“The semipostal stamp was a popular choice for holiday gift-giving.”
2. noun
A postage stamp that contributes a portion of its face value to a charity or cause.
“She bought a semipostal to support the local animal shelter.”