Instance
Middle English: via Old French from Latin instantia ‘presence, urgency’, from instare ‘be present, press upon’, from in- ‘upon’ + stare ‘to stand’. The original sense was ‘urgency, urgent entreaty’, surviving in at the instance of . In the late 16th century the word denoted a particular case cited to disprove a general assertion, derived from medieval Latin instantia ‘example to the contrary’ (translating Greek enstasis ‘objection’); hence the meaning ‘single occurrence’.
wiktionary
From Middle French instance, from Latin instantia(“a being near, presence, also perseverance, earnestness, importunity, urgency”), from instans(“urgent”); see instant.
etymonline
instance (n.)
late 14c., "urgency, insistence" (a sense now archaic), from Old French instance "effort, application; urgency, eagerness, anxiety" (13c.), from Latin instantia "presence, effort, intention; earnestness, urgency," literally "a standing near," from instans (see instant).
In logic, "a fact, a case, an example" (a sense in English from early 15c.), from Medieval Latin instantia, which translated Greek enstasis. This led to for instance "as an example" (1650s), and the noun phrase give (someone) a for instance (1953, American English). The general sense "anything that illustrates a general type" was in use by 19c.
instance (v.)
"cite as an instance" (in the logical sense), c. 1600, from instance (n.). Middle English had a verb instauncen "to plead with, urge, entreat." Related: Instanced; instancing.
