is there a word for this: Two people, simultaneously in the a.m. or p.m. of a day, are they in the same hemi-meridian? Hemi-chron?


hankuri, welcome to the board. It looks like we are all going to answer your questions with another question! Don't let that put you off; there is a wealth of talent here if you can structure the question correctly.

I think you are asking for a word that describes the 180° longitude either side of the current position of the sun, or did you wish to include such complications such as time zones and Daylight Saving Time? I can't think of one right now. As the day progresses, people around the world would fall in and out of the same half-day/hemi-chron. We already talk of the Western/Eastern and Northern/Southern hemispheres but these are fixed, whereas the am/pm one changes continually. Maybe "ante meridian hemisphere" and "post meridian hemisphere" are sufficient. Although "hemi-chron" looks and sounds all right (to me), it is not immediately obvious what is meant, and might get confused with he-micron - whatever that might be)

Rod