means An observable fact, event, or experience — something that occurs and can be perceived, often one remarkable enough to draw notice.

from From Greek phainomenon, 'a thing appearing to view,' from phainesthai, 'to appear,' which traces back to phainein, 'to bring to light' or 'show.' It entered English in the late 16th or early 17th century through scientific and philosophical use — the very root that also gives us 'phantom' and 'fantasy,' all clustered around the idea of something coming into sight. Fittingly, a phenomenon was always, at heart, just a thing that shows up.