Share this entry

permanent hardness Line breaks: per¦man|ent hard|ness

Definition of permanent hardness in English:

noun

[mass noun]
The presence in water of mineral salts (chiefly calcium sulphate) that are not removed by boiling.

Share this entry

 

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day innocuous
Pronunciation: ɪˈnɒkjʊəs
adjective
not harmful or offensive