essential /ɪˈsɛn.ʃəl/adjective 8noun 2forms 3 adjective8 •completely necessary and not to be left outThere’s canker at the root, your seed Denies the blessing of the sun, The light essential to your need. Your hopes are murdered and undone. — 1941 •Very important; of high importance.I see it as essential that there should be somewhere to park. •Necessary for survival but not synthesized by the organism, thus needing to be ingested. •Being in the basic form; showing its essence.Don’t mind him being grumpy. That’s the essential Fred. •Idiopathic. •Having the nature of essence; not physical. •Really existing; existent.Or is it true, that thou art but a bare name, / And no essential thing? — 1612 •Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold. noun2 •A necessary ingredient. •A fundamental ingredient. formsessentials · more essential · most essential