Meaning of ESSENTIAL in English
[ ɪ'sɛnʃ(ə)l ]
1》 absolutely necessary; extremely important.
2》 central to the nature of something; fundamental: the ~ weakness of the plaintiff's case.
3》 (of an amino acid or fatty acid) required for normal growth but not synthesized in the body and therefore necessary in the diet.
4》 Medicine (of a disease) with no known external stimulus or cause; idiopathic.
■ noun ( ~s )
1》 things that are absolutely necessary.
2》 the fundamental elements of something.
ME (in the sense 'in the highest degree'): from late L. ~is , from L. essentia (see essence ).
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004