the.com/sighting

means An instance of seeing or noticing someone or something, especially something rare, elusive, or notable — a spotting.

from A straightforward formation from 'sight' plus the noun-making suffix '-ing,' which turns an act of seeing into a countable event. 'Sight' itself traces back through Old English 'sihth' or 'gesiehth,' rooted in the Germanic verb 'seon,' to see — the same ancient root that gives English 'see.' The specific sense of 'sighting' as a noun for a reported spotting (of a ship, a UFO, a rare bird, a celebrity) is a relatively modern narrowing, gaining real traction in the 19th and 20th centuries alongside the rise of reported sightings of exactly the unverifiable, exciting kind the essence teases.