Phenomenon

[1] The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which cannot be directly observed.

Kant was heavily influenced by Gottfried Wilhelm Leibniz in this part of his philosophy, in which phenomenon and noumenon serve as interrelated technical terms.

Far predating this, the ancient Greek Pyrrhonist philosopher Sextus Empiricus also used phenomenon and noumenon as interrelated technical terms.

According to the Dictionary of Visual Discourse:[2]In ordinary language 'phenomenon/phenomena' refer to any occurrence worthy of note and investigation, typically an untoward or unusual event, person or fact that is of special significance or otherwise notable.In modern philosophical use, the term phenomena means things as they are experienced through the senses and processed by the mind as distinct from things in and of themselves (noumena).

[3] Thus, the term phenomenon refers to any incident deserving of inquiry and investigation, especially processes and events which are particularly unusual or of distinctive importance.

The combustion of a match is an observable occurrence, or event, and therefore a phenomenon.
A comparison between a candle flame on Earth (left) and in a microgravity environment, such as that found on the International Space Station (right).
The same burning phenomenon is observed , but different flame shape and colouring phenomena are also observed.
Cloud chamber phenomena. Scientists use phenomena to refine some hypotheses and sometimes to disprove a theory . See also animated version .