Anything that's deserving of praise or a reward could be described as meritorious.
Meritorious things deserve a lot of merit, usually because they were very brave or noble in some way. If you saved a person from drowning, that's meritorious. Firefighters and doctors have meritorious careers because they're dedicated to helping people. Giving money to charity is meritorious. When something is meritorious, it deserves praise and thanks.