Semipostals are stamps that are sold for more than their postage value, with the extra money going to a specific cause or charity.
Semipostals are a way to help others while sending mail.
Examples:
I bought some semipostals to support the animal shelter.
The semipostals help raise money for sick children.
She collects semipostals for her stamp collection.
The semipostals have pretty pictures on them.
The semipostals cost a little more, but it's for a good reason.
We used semipostals to send letters to grandma and help other people at the same time.