Synonym Discussion of essential. essential, fundamental, vital, cardinal mean so important as to be indispensable. essential implies belonging to the very nature of a thing and therefore being incapable of removal without destroying the thing itself or its character conflict is essential in drama.
The definition of a cretin is a very stupid person, or a person suffering from the disease cretinism, which causes mental problems and deformity. An example of a cretin is a person who constantly makes stupid and horrible mistakes. 2  An example of a cretin is someone with physical deformities due to the disease.
Cristae. Definition. noun, singular: crista. (cell biology). The infoldings or inward projections of the inner membrane of the mitochondrion, which are studded with proteins and increase the surface area for chemical reactions to occur like cellular respiration.(anatomy). Crests or ridges projecting from a surface, as in cristae cutis (dermal ridges on palms and soles).he infoldings or inward projections of the inner membrane of the mitochondrion, which are studded with proteins and increase the surface area for chemical reactions to occur like cellular respiration. (anatomy).