IPA: /əˈkɔːrdəns/
KK: /əˈkɔrdəns/
A state of being in agreement or following rules, instructions, or standards.
The project was completed in accordance with the guidelines provided.
Accordance is formed from "accord" (from Old French *acorder*, meaning to agree) and the suffix "-ance" (meaning the state or quality of). The word "accordance" refers to the state of agreeing or being in harmony with something.
Think of 'agreeing' ('accord') and the state of that agreement ('-ance') — that's what accordance means.