Word of the Day: Ephemeris

This is another word related to time. The Greek hemera means 'day'; if you go to Greece you will hear people greeting each other with "Kalémera!" which comes from kalli- meaning 'good, beautiful' and hemera — that is, 'Good day!'

So what does 'ephemeris' mean?

The forms 'ephemera' and 'ephemeral' are probably more common. They come from the Greek preposition ep(i)- which means 'on' or 'on the surface of', and hemera. 'Ephemeral' therefore means '(only) on the day' and 'ephemera' literally means 'things that are (only) on the day'. Figuratively, they refer to things that are transient, that pass quickly and are gone, that touch us lightly and thus have less value in terms of durability and impact.

An ephemeris, however, is a book of days. Technically, it's an astronomer's guidebook which lists data related to known celestial bodies for a given day, and gives calculations and calculated information based on that data.

It's a lovely word, isn't it? You could call your diary an ephemeris if you were so minded. Until the next time, Kalémera!