IPA: /ˈɡriːtə/
KK: /ˈɡriːtər/
A person who welcomes or says hello to others when they arrive.
The greeter at the entrance made everyone feel welcome.
Greeter is formed from "greet" (from Old English "gretan", meaning to approach or address) and "-er" (meaning a person who). A greeter is a person who approaches or addresses others, typically to welcome them.
Think of someone who 'approaches' ('gretan') to 'welcome' others — that's what a greeter does.