IPA: /əˈtɛndər/
KK: /əˈtɛndər/
A person who goes to or is present at a particular event, meeting, or place.
The attender took notes during the conference to remember the important points.
Attender is formed from "attend" (from Old French *atendre*, meaning to stretch toward or to wait for) and "-er" (meaning a person who). The word "attender" refers to a person who attends or is present at an event or gathering.
Think of someone who is 'stretching toward' or 'waiting for' something — that's why an attender is a person who is present at an event.