rarefaction
(noun) a decrease in the density of something; “a sound wave causes periodic rarefactions in its medium”
Source: WordNet® 3.1
rarefaction (countable and uncountable, plural rarefactions)
A reduction in the density of a material, especially that of a fluid.
• compression
Source: Wiktionary
Rar`e*fac"tion, n. Etym: [Cf. F. raréfaction. See Rarefy.]
Definition: The act or process of rarefying; the state of being rarefied; - - opposed to condensation; as, the rarefaction of air.
Source: Webster’s Unabridged Dictionary 1913 Edition
21 April 2025
(noun) a reference work (often in several volumes) containing articles on various topics (often arranged in alphabetical order) dealing with the entire range of human knowledge or with some particular specialty
According to Guinness World Records, on 25 September 2016, the Birla Institute of Management Technology (India) in Uttar Pradesh, India, constructed the largest coffee cups pyramid consisting of 23,821 cups. They used paper takeaway coffee cups to build the pyramid.
