*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 the philosophical sense of "voluntary agency" (embracing desire and volition), 1836, from Latin conationem (nominative conatio) "an endeavoring, effort," noun of action from past participle stem of conari "to endeavor, to try," from PIE *kona-, from root *ken- "to hasten, set oneself in motion" (see deacon).
Middle English deken, "one who reads the Gospel in divine worship, one of a body of assistants to a priest or other clergyman," from Old English deacon, diacon, from Late Latin diaconus, from Greek diakonos "servant of the church, religious official," literally "servant," from dia- here perhaps "thoroughly, from all sides," + PIE *kon-o-, from root *ken- "to hasten, set oneself in motion." Related: Deaconess; deaconship.
early 15c., legal, "a charge, a formal accusation," from Old French surmise "accusation," noun use of past participle of surmettre (see surmise (v.)). Meaning "inference, guess" is first found in English 1580s.
Then felt I like some watcher of the skies
When a new planet swims into his ken;
Or like stout Cortez, when with eagle eyes
He stared at the Pacific—and all his men
Look'd at each other with a wild surmise—
Silent, upon a peak in Darien.