call it a day, to

To stop work for the time being. The phrase implies that a full day’s work has been done, whether or not the clock so indicates. Indeed, J. C. Neal in Charcoal Sketches (1838) spelled this out: “I’ve a great mind to knock off and call it half a day.” call it quits, to To stop doing something, either permanently or temporarily. Quits here has the meaning of acquittal or discharge, that is, release from obligation; the implication is that one has done enough and so has discharged one’s obligation. American in origin, the expression appears in a letter of Jack London’s (1898): “Tomorrow I would cut my throat and call quits with the whole cursed business.”