IPA: /meɪnˈteɪnər/
KK: /meɪnˈteɪnər/
A person or thing that keeps something in good condition or ensures it continues to function properly.
The maintainer checked all the equipment to ensure it was working correctly.
Maintainer → It is formed from "maintain" (from Old French *maintenir*, meaning to hold or keep) and "-er" (meaning a person who). A maintainer is a person who holds or keeps something in a certain state or condition.
Think of someone who 'holds' ('maintain') something in a good condition — that's what a maintainer does.