You probably know that a fortnight is equal to 14 days.
However, you probably didn't know that there are a bunch more units like that. mostly Ancient Roman.
Here's a list of a few of my favorites:
| Unit | Value | Usage/Source/Trivia |
|---|---|---|
| Jiffy | 1/60 or 1/50 seconds | The frequency of most alternating current power supplies |
| Punct | 15 Minutes | 1/4 of an hour |
| Mileway | 20 Minutes | The approximate time it takes to walk a mile |
| Watch | 4 Hours | A British Naval term where a day was divided into 6 watches |
| Nundine | 9 Days | Ancient Roman market was held every 9 days |
| Tredecium | 13 Days | Some ancient calendar systems were 13-day weeks |
| Quarantine | 40 Days | Italian sailors had to stay isolated for 40 days if their ship had a plague |
| Olympiad | 4 Years | Ancient Roman Olympics were held every four years (modern Olympics are too!) |
| Lustrum | 5 Years | Ancient Roman population census was taken every 5 years |
| Indiction | 15 Years | Ancient Romans used it for tax cycles |
~Ethan