IPA: /ədˈmɪtə/
KK: /ədˈmɪtər/
A person or thing that allows or accepts something to enter or be included.
The hospital has a dedicated team of admitters who process patient entries.
Admitter is formed from "ad-" (meaning to) and "mittere" (meaning to send). The word describes someone who sends or allows something to enter or be accepted.
Think of someone 'sending' ('mittere') something 'to' ('ad-') allow it to enter — that's why an admitter is someone who allows entry.