Fatwoods are highly prized sources of kindling. They are composed of resin-rich fibers that help to ignite fires more easily. There are several synonyms for the term, fatwoods. These include lighter wood, heartwood, pine knots, and kindling. The term lighter wood generally refers to any wood that is used for starting fires. Heartwood is a synonym for fatwood that refers to the central, non-living part of a tree trunk that is rich in resins. Pine knots refer specifically to the small, knotty pieces of fatwood that can be found in the heartwood of pine trees. Kindling is a more general term that refers to any small, dry pieces of wood used to start a fire.