What's the difference between oil shale and shale oil?

Oil produced from shale reservoirs, often called shale oil.

Oil shale is an inorganic rock that contains a solid organic compound known as kerogen. Oil shale is a misnomer because kerogen isn't crude oil, and the rock holding the kerogen often isn't even shale.

A type of sedimentary rock composed chiefly of a combination of silt and clay. Shale may contain kerogen, a type of organic matter that yields oil and gas. Shale formations are best known for shale oil, a type of unconventional oil.The oil coming out of the shale is referred to as shale oil or tight oil.

Oil shale is essentially rock that contains solid bits of kerogen – a precursor to oil. All oil is from organic matter that is subjected to intense heat and pressure until it breaks down into hydrocarbons.