necessary labour time
Marxian economics term: the portion of the working day during which a worker produces the value equivalent to their own subsistence.
In Marxian economics, necessary labour time and surplus labour time are distinguished.
Surplus labour time: the portion of the working day beyond necessary labour time, during which surplus value is produced.
socially necessary labour time
Compound of 必要 (necessary) + 労働 (labour) + 時間 (time), calque of German 'notwendige Arbeitszeit' as used in Marxian economics.