This term specifically describes visual or physical harmony rather than an abstract balance of forces. It differs from 均衡 (きんこう), which applies to concepts like budgets or power dynamics where two sides are equal in weight. While 均衡 (きんこう) suggests a leveling of forces, this word implies an aesthetic beauty derived from proper arrangement.
You will most frequently encounter the phrase 均整の取れた (きんせいのとれた) to describe something that is “well-proportioned.” It commonly compliments a fit body or a carefully designed artistic structure.