IPA: /əˈmiːliəreɪtə/
KK: /əˈmiːliəreɪtə/
A person or thing that makes a situation better or improves something.
The ameliorator of the community worked tirelessly to improve living conditions.
Ameliorator is formed from "ameliorare" (meaning to make better) and the suffix "-or" (meaning one who). The word refers to one who makes things better or improves a situation.
Think of someone who is making things 'better' ('ameliorare') — that's why an ameliorator is someone who improves a situation.