From Longman Dictionary of Contemporary Englishwhitenerwhit‧en‧er /ˈwaɪtnə $ -ər/ (also whitening /ˈwaɪtnɪŋ/) noun [countable, uncountable] CCa substance used to make something more white
Examples from the Corpus
whitener• They can be purchased as liquid, frozen liquid, or spray-dried coffee whitener. 