Is alkyd water or oil?

Alkyd is oil-based, not water-based, though there are modern waterborne alkyd hybrids. Traditional alkyd paint is oil-based paint made from alkyd resins, which are synthetic resins made by reacting polyols and dicarboxylic acids with fatty acids from vegetable oils, so it is classified as oil-based or solvent-based, using mineral spirits or paint thinner as solvent, curing by oxidation. It has strong odor, slow drying, and requires solvent for cleanup. Because of VOC regulations and desire for easier cleanup, manufacturers developed waterborne alkyds or water-based alkyds, which are alkyd resins emulsified in water, so they look and clean up like latex with soap and water but cure to a hard alkyd-like finish. These are often labeled waterborne alkyd, hybrid alkyd, or alkyd enamel water-based. So traditional alkyd is oil, waterborne alkyd is water-based emulsion of alkyd resins. When someone says alkyd paint, they usually mean oil-based alkyd unless specified as waterborne alkyd. So answer is alkyd is oil-based, but waterborne versions exist that are water-based.