Science & TechnologyGreek → English
Anhydrous
/anˈhaɪdrəs/adjective
Containing no water, especially no water chemically bound into a compound's crystal structure.
The Greek roots
ἀν-
an-
without
ὕδωρ
hýdōr
water
Literally: “waterless”
The story of the word
Greek ἄνυδρος described a dry country with no springs long before chemists took it for crystals stripped of their water. The distinction is visible on a shelf: hydrated copper sulfate is blue, and heating it to anhydrous white and then dripping water back on is a standard school demonstration. The prefix takes an n before a vowel, the same rule that gives anaemia against apathy.
- How it travelled
- Ancient Greek → Latin → English
- First recorded
- 19th century
Same family
hydrantdehydratehydraulicanaemiaanarchy
In a sentence
The reaction needs anhydrous conditions, so the glassware goes in the oven first.
Anhydrous ammonia is stored under pressure as a liquid.