From Longman Dictionary of Contemporary Englishsoftenersoft‧en‧er /ˈsɒfənə $ ˈsɒːfənər/ noun [countable, uncountable] DHCa substance that you add to water to make clothes feel soft after washing fabric softener → water softener
Examples from the Corpus
softener• Thus the volume of water that a softener can soften before regeneration is a function of the hardness content of the water.• a fabric softener• One is chemical, using either a metal softener or corrosive.• No other powder or softener is needed.• The second is to install a water softener into the cold water supply.• A water softener must be fitted after the supply to the drinking water so that this is left providing hard water for drinking.• Benckiser is best known for its Calgon water softener.• Water conditions have an important effect on their performance as do the correct functioning of water softeners if fitted.• So water softeners are added to washing powders to prevent its formation. 