1. (noun) A naturally occuring trace fossil (a naturally-formed mold) formed when a fine-grained matrix solidifies within (most often) the neurocranium (brain-case) of a skull. The endocast can then either remain within a wholly or partially intact neurocranium, or can remain intact and independent of the neurocranium once the latter has been broken away either taphonomically (prior to discovery) or after discovery (either accidentally or intentially during preparation or later handling). 2. (noun) A mold (or derivative cast) made of an endocranial space in order to better visualize endocranial morphology which might otherwise be difficult or impossible to see directly. Such endocasts are often used to study the morphology of the meningeal, arterial, and venous impressions left by brain structures on the inside of the neurocranium.
