Danish oil is a wood finishing oil, often made of tung oil or polymerized linseed oil. Because there is no defined formulation, its composition varies among manufacturers.
Danish oil is a hard drying oil, meaning it can polymerize into a solid form when it reacts with oxygen in the atmosphere. It can provide a hard-wearing, often water-resistant satin finish, or serve as a primer on bare wood before applying paint or varnish. It is a "long oil" finish, a mixture of oil and varnish, typically around one-third varnish and the rest oil.