• fluctuate •Pronunciation: flêk-chU-weyt • Hear it!
Part of Speech: Verb, intransitive
Meaning: 1. To rise and fall in waves, to undulate. 2.To vary or waver, to undergo alternating changes, to vacillate.
Notes: Today's word has a large derivative family. The adjective is fluctuant "fluctuating, wavering, unstable" and the noun, fluctuation. Of course, you can use fluctuating in the same sense and fluctuational can also assume the responsibilities of fluctuant. Fluctuable has been used in the sense of "capable of fluctuating", though not recently.
In Play: Today's Good Word applies to anything that waves or undulates, "The field of wheat was fluctuating in the wind for as far as the eye could see." It is also finds applications far away from physical waves: "Heidi Claire's opinion fluctuates more than the temperature."
Word History: Latin fluctuare "to undulate, wave" from fluctus "a flowing", the noun from the past participle of fluere "to flow". As we have seen many times before, the [f] at the beginning of a Latin word often goes back to PIE [bh], a with a puff of air. The original PIE root of this word was *bhleu- "to swell, well up". So, it is the source of English blow and bloat, as well as all the words borrowed from Latin containing flu. Flu itself? Yes, it came from the Italian version of influence, influenza based on the assumption that epidemics were caused by the influence of the stars. (Today's word is another indication of the unfluctuating good influence of Paul Ogden's suggestions on our Good Word series.)