Essential \Es*sen"tial\, a. [Cf. F. essentiel. See Essence.]

1. Belonging to the essence, or that which makes an object, or class of objects, what it is.

Majestic as the voice sometimes became, there was forever in it an essential character of plaintiveness. --Hawthorne.

2. Hence, really existing; existent.

Is it true, that thou art but a a name, And no essential thing? --Webster (1623).

3. Important in the highest degree; indispensable to the attainment of an object; indispensably necessary.

Judgment's more essential to a general Than courage. --Denham.

How to live? -- that is the essential question for us. --H. Spencer.

4. Containing the essence or characteristic portion of a substance, as of a plant; highly rectified; pure; hence, unmixed; as, an essential oil. ``Mine own essential horror.'' --Ford.

Source: Webster's Revised Unabridged Dictionary (1913)