from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Lasting three days.
- adj. Happening every third day.
- n. An event lasting three days.
from the GNU version of the Collaborative International Dictionary of English
- adj. Lasting three lays; also, happening every third day.
from The Century Dictionary and Cyclopedia
- Lasting three days, or happening every third day.
From triduum ("space of three days"). (Wiktionary)