noun
: a polymer of vinyl alcohol ; especially : a thermoplastic resin that is soluble or swells in water, that if obtained by complete hydrolysis of polyvinyl acetate has the formula [−CH 2 CH(OH)−] x or if by partial hydrolysis contains some acetate groups, and that is used chiefly as emulsifiers, adhesives, and films resistant to solvents and abrasion, and in making molded and extruded products and polyvinyl acetals