Definition of: phenomenon

(fi·nom′ə·non) noun plural ·na (-nə)
1. Something visible or directly observable, as an appearance, action, change, or occurrence of any kind, as distinguished from the force by which, or the law in accordance with which, it may be produced.
2. Any unusual occurrence; an inexplicable fact; marvel; prodigy.
3. Any fact, appearance, or occurrence in consciousness; that which is apprehended by the senses, in contrast with or in opposition to that which really exists, or to things in themselves: contrasted with noumenon.
4. A symptom of disease. [<LL phaenomenon <Gk. phainomenon an appearance, orig. ppr. passive neut. of phainein show]