I’ve just watched the third of mathematician Marcus du Sautoy’s television series Precision: The Measure of All Things on BBC 4.

There’s a lot been going on at Son of the Rock Towers over the past week or two (details may be forthcoming in due course) so I missed the first two episodes, Time and Distance and Mass and Moles – which is a pity as the second at least will have been about Chemistry – and I don’t know if I’ll get the chance to catch up on them.

Tonight’s last in the series was titled Heat, Light and Electricity and discussed how ways to measure these phenomena have been developed and extended over time.

du Sautoy irritated me though by using the word phenomena as if it were singular. I now quote Wikipedia:-

Phenomena are observable events, particularly when they are special.

A single observable event is of course a phenomenon.

The same distinction applies to the word criterion – like phenomenon, based on Greek – and its plural where too many people, especially news reporters, refer to a criteria. It makes me cringe.

In sum, the only criterion for using the word phenomena is that more than one event is involved. If there’s only a single event then it’s a phenomenon.