Something having real, demonstrable existence
One that evokes great surprise and admiration
There are UFO groups which investigate the UFO phenomenon.
The insect showed the phenomenon of long-lived luminescence.
There was a phenomenon to suggest ways in which they could investigate the activities that were going on.
In the early 1980s, US doctors began to notice a strange phenomenon.
One interesting phenomenon in spider-life seems to be directly and certainly traceable to this influence, and that is mimicry of ants.