Meaning

noun the principal activity in your life that you do to earn money

noun a specific piece of work required to be done as a duty or for a specific fee

noun a workplace; as in the expression

originFrom the phrase jobbe of work (“piece of work”), of uncertain origin. Perhaps from a variant of Middle English gobbe (“mass, lump”); or perhaps related to Middle English jobben (“to jab, thrust, peck”), or Middle English choppe (“piece, bargain”). More at gob, jab, chop.

Etymology from Wiktionary, CC BY-SA 3.0