IPA: /ˈnoʊtɪfaɪər/
KK: /ˈnoʊtɪfaɪər/
A person or thing that informs or alerts someone about something.
The notifier sent an alert about the upcoming meeting.
Notifier → It is formed from "notify" (from Latin "notificare", meaning to make known) and "-er" (meaning a person who). A notifier is a person who makes something known or informs others.
Think of someone who 'makes known' ('notify') information — that's why a notifier is a person who informs.