noun
Western-style age; completed years of age
Refers to age counted by fully completed years since birth, as opposed to the traditional Japanese 数え年 system. Common in legal and official documents.
日本では、法律上の年齢は満年齢で計算されます。
In Japan, legal age is calculated using the Western-style completed-years system.
満
By Western-style age he is still 19, but by the traditional Japanese count he is 20.