mid-14c., nobilite, "honor, renown; majesty, grandeur;" late 14c., "quality of being excellent or rare," from Old French nobilite "high rank; dignity, grace; great deed" (12c., Modern French nobilité), and directly from Latin nobilitatem (nominative nobilitas) "celebrity, fame; high birth; excellence, superiority; the nobles," from nobilis "well-known, prominent" (see noble (adj.)).
Meaning "quality of being of noble rank or birth; social or political preeminence, usually accompanied by hereditary privilege" is attested from late 14c.; sense of "the noble class collectively" is from late 14c. Sense of "dignity of mind, elevation of the soul, loftiness of tone" is from 1590s.
*gnō-, Proto-Indo-European root meaning "to know."
It forms all or part of: acknowledge; acquaint; agnostic; anagnorisis; astrognosy; can (v.1) "have power to, be able;" cognition; cognizance; con (n.2) "study;" connoisseur; could; couth; cunning; diagnosis; ennoble; gnome; (n.2) "short, pithy statement of general truth;" gnomic; gnomon; gnosis; gnostic; Gnostic; ignoble; ignorant; ignore; incognito; ken (n.1) "cognizance, intellectual view;" kenning; kith; know; knowledge; narrate; narration; nobility; noble; notice; notify; notion; notorious; physiognomy; prognosis; quaint; recognize; reconnaissance; reconnoiter; uncouth; Zend.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit jna- "know;" Avestan zainti- "knowledge," Old Persian xšnasatiy "he shall know;" Old Church Slavonic znati "recognizes," Russian znat "to know;" Latin gnoscere "get to know," nobilis "known, famous, noble;" Greek gignōskein "to know," gnōtos "known," gnōsis "knowledge, inquiry;" Old Irish gnath "known;" German kennen "to know," Gothic kannjan "to make known."
In application to things nobleness is rather more appropriate than nobility, as the nobleness of architecture or one's English, while nobility is more likely to be applied to persons and their belongings, as nobility of character or of rank; but this distinction is no more than a tendency as yet. [Century Dictionary, 1895]