equal relationship; equal footing
Refers to a relationship where parties have equal status, power, or rights, without hierarchy.
I want to discuss this on an equal footing, not as boss and subordinate.
Both countries aim to build an equal relationship.
平等 means equality in a broader sense (equal treatment, equal rights), while 対等関係 specifically refers to a relationship or footing between parties.
上下関係 is a hierarchical relationship, the opposite of 対等関係.
Compound of 対等 (equal, on par) and 関係 (relationship).