zeitgeber
n.— «Light and temperature are the only periodic or quasi-periodic environmental variables to which endogenous oscillation can be coupled: in nature they entrain the endogenous oscillation, thereby controlling period and establishing appropriate phase. They are, to use Aschoff’s phrase, the principal Zeitgeber.» —“On the Significance of Transients in Daily Rhythms” by Colin Pittendrigh, Victor Bruce, Peter Kaus Proceedings of the Natl. Acad. of Sciences (US) Sept. 15, 1958. (source: Double-Tongued Dictionary)
Further reading
An anadrome is a word that forms a whole new word when you spell it backwards. For example, the word “stressed” spelled backwards is “desserts.” Some people’s first names are anadromes. There’s the girl named Noel...
A flashlight doesn’t flash. It provides a steady beam of light. So why is it called a flashlight? The earliest versions lit up only briefly before the batteries gave out and required a recharge, so they were literally “flash lights...