pretreat

verb

treat once, usually with a chemical, before the main cure

Wiktionary

verb

Etymology: Etymology tree Proto-Indo-European *per- Proto-Indo-European *preh₂- Proto-Indo-European *-i Proto-Indo-European *préh₂i? Proto-Italic *prai Proto-Italic *prai- Latin prae-lbor. Middle English pre- English pre- English treat English pretreat From pre- + treat.

To give something a treatment prior to another operation.