Saturation — the state in which a substance or system can no longer absorb more of a component (chemical saturation), or when demand/interest is fully satisfied (market or satiation).
溶液が飽和して、それ以上は溶けない。
The solution is saturated and nothing more will dissolve.
スマートフォン市場は飽和状態に近づいていると言われる。
It is said that the smartphone market is approaching saturation.