essence: [14] Essence and its derivative essential [14] are the English descendants of the Latin verb ‘to be’, esse (which came ultimately from the Indo-European base *es- ‘be’, source also of English is). From it was formed the abstract noun essentia ‘being, existence’, acquired by English through Old French essence. In the adjective essential, the sense ‘absolutely necessary’ developed via ‘inherent’ and ‘indispensable’ in the 16th century. => is
