Greek for “originating from within a system”; means that something occurs due to an internal cause or from within a system and has either inward or outward effect.

According to this, endogenous inclusions in the structure originate from chemical reactions within the system and have not been introduced from the outside. Consequently, an endogenoussolidification type (or solidification morphology) is understood as the solidification behavior of an alloy in a way that crystals are formed inside the melt prior to the actual solidification front (e.g. in nodular graphite cast iron).

In contrast to that: exogenous.