First recorded in 1350–1400.
Comes via Middle English from the Latin word tortuōsus, which derives from the verb torquēre, “to twist, bend.”
Sign up for more Word of the Day!

\r\nEXAMPLES OF TORTUOUS\r\n

The tortuous road through the mountains made for a challenging but scenic drive.
The author's writing style was known for its elegant prose and tortuous plot twists.

\r\nIt's National Poetry Month, and we’ve created a challenge that really is for everyone. Submit now!","audio":"https://static.sfdict.com/audio/T03/T0390200.mp3","definitions":[{"partofspeech":"adjective","data":"full of twists, turns, or bends; twisting, winding, or crooked."}],"examples":[],"imageUrl":"https://www.dictionary.com/e/wp-content/uploads/2024/03/tortuous_IG.png","accentColor":"#0063D7"}},"status":"succeeded"}},"meta":{"requestId":"sQDpqXX0I8Y4QDyb6y-q2","requestStatus":"fulfilled"}},{"type":"fetchWordsNearby/fulfilled","payload":{"data":{"before":[{"slug":"diffused-junction","entry":"diffused junction"},{"slug":"diffuse-porous","entry":"diffuse-porous"},{"slug":"diffuser","entry":"diffuser"},{"slug":"diffusible","entry":"diffusible"},{"slug":"diffusion","entry":"diffusion"}],"after":[{"slug":"diffusionism","entry":"diffusionism"},{"slug":"diffusion-line","entry":"diffusion line"},{"slug":"diffusion-model","entry":"diffusion model"},{"slug":"diffusive","entry":"diffusive"},{"slug":"diffusivity","entry":"diffusivity"}]}},"meta":{"arg":{"word":"diffusion-coefficient"},"requestId":"WNQn4NevQxfl8qoQK_mFZ","requestStatus":"fulfilled"}},{"type":"luna/fetchExampleSentences/fulfilled","payload":{"data":{"tdb":[],"gbg":[]}},"meta":{"arg":{"word":"diffusion-coefficient"},"requestId":"DidGNlwIpTq8htRMqx-NB","requestStatus":"fulfilled"}},{"type":"fetchDictionaryResults/fulfilled","payload":{"slugs":[{"entries":[{"__typename":"CollinsEntry","headword":{"displayForm":"diffusion coefficient","slug":"diffusion-coefficient"},"homonym":null,"note":null,"origin":null,"partOfSpeechGroups":[{"definitions":[{"crossReferencesConnection":{"edges":[]},"definitionSetChunks":"[{\"type\": \"defgrp\", \"children\": [{\"text\": \"the rate at which a diffusing substance is transported between opposite faces of a unit cube of a system when there is unit concentration difference between them\", \"type\": \"text\"}]}, {\"text\": \"D\", \"type\": \"text\"}, {\"text\": \"Also calleddiffusivity\", \"type\": \"text\"}]","examples":[],"idiom":null,"ordinal":1,"sense":null,"subdefinitions":[]}],"ordinal":1,"partOfSpeech":"noun"}],"pronunciations":[],"subEntry":[]}],"url":"diffusion-coefficient"}]},"meta":{"arg":{"slug":"diffusion-coefficient"},"requestId":"_-yeX1kZjId1D_e5Sds5U","requestStatus":"fulfilled"}},{"type":"fetchResultsData/fulfilled","payload":{"data":{"url":"diffusion-coefficient","displayForm":"diffusion coefficient","canonicalSlug":"diffusion-coefficient","content":[{"source":"collins","entries":[{"id":"u11d1def534ea1be0.1a3ea532.11d23ea3852.-2cf3.1","type":"normal","entry":"diffusion coefficient","entrySyllabified":null,"entryVariants":"diffusion constant","homograph":null,"pronunciation":{"audio":null,"spell":null,"ipa":""},"predefinitionContent":"","posBlocks":[{"pos":"noun","posSupplementaryInfo":"","definitions":[{"order":1,"type":"simple","predefinitionContent":"","definition":"the rate at which a diffusing substance is transported between opposite faces of a unit cube of a system when there is unit concentration difference between them","postdefinitionContent":"Symbol: D Also called: diffusivity"}]}],"origin":"","supplementaryNotes":[],"variantForms":[],"referenceData":[],"relatedForms":[],"derivedForms":[]}]}],"nearbyWordOrdinal":43515,"index-rank-01":["diffusion coefficient"],"index-rank-02":[],"index-rank-03":[],"index-rank-04":[],"index-rank-05":[],"index-rank-06":[],"index-rank-07":[],"index-rank-08":[],"index-rank-09":[],"index-rank-10":[],"index-rank-11":[],"index-rank-12":[],"index-rank-13":[],"index-rank-14":[],"index-rank-15":[],"tunaSlug":null,"isFeaturedMetaSlug":false}},"meta":{"arg":{"word":"diffusion-coefficient"},"requestId":"1-5fH05-eTivJ5AG0db6c","requestStatus":"fulfilled"}},{"type":"fetchSpellSuggestions/fulfilled","payload":{"data":{"luna":[],"tuna":[],"lunaWithSlug":[],"tunaWithSlug":[]}},"meta":{"arg":{"word":"diffusion-coefficient"},"requestId":"9reA7DqDZoFGl6IBPruuD","requestStatus":"fulfilled"}}]},"actionData":null,"errors":null}

diffusion coefficient

noun

Word of the Day