noun
coordinate relation
Computing term for a relationship between elements of equal rank or status, such as in data structures or formal grammars.
XMLでは、同格関係にある要素は同じ階層に属する。
In XML, elements in a coordinate relation belong to the same level.
Compound of 同格 (same rank) and 関係 (relation). The exact derivation is uncertain; the term is used in technical computing contexts.