In time, why are seconds called seconds?

This is an excellent question that speaks to how our notions of time have evolved with technology

To explain a second, we need to start with a minute. The word minute was derived from Latin and carried the notion of a small interval. When you divide an hour into 60 equal pieces, you get a very small - or "minute" (as in, accent on the SECOND syllable) - length of time

The word second is short for "second minute," meaning a second division into small pieces (60 again), a sort of second order of minuteness. A second was considered a very short time indeed.

This sort of small unit arose only around 1391 when technology - specifically the advent of mechanical timekeeping devices - made the concept meaningful.

Before that, people would refer to times easy to determine from natural phenomena: midday, sunrise, sunset, etc. They were a lot more relaxed about time, and lived more in har- mony with natural cycles.