Meaning of ESSENTIAL in English

ESSENTIAL

I . a.

1.

Vital, necessary, requisite, indispensable, highly important.

2.

Volatile, diffusible, pure, highly rectified.

3.

( Med. ) Idiopathic.

II . n.

[ Usually in pl. ]

1.

Indispensable element, vital part, absolute requisite.

2.

Rudiment, first principle, first step, outline.

Soule. Dictionary of English synonyms.      Словарь английских синонимов.