noun-modifying (irregular)
Technical term used in mathematics, statistics, and science to describe an additive property or effect. Appears in compounds like 相加平均 (arithmetic mean) and 相加作用 (additive action).
The arithmetic mean is the value obtained by dividing the sum of the data by the number of items.
この薬の成分には相加作用がある。
The ingredients of this medicine have an additive effect.
Compound of 相 (mutual, together) and 加 (add). The exact historical derivation is uncertain, but the word is used in modern technical vocabulary to mean 'additive'.