challange

US

UK

A1
n.NounA call to someone to participate in a competitive situation or fight to decide who is superior in terms of ability or strength.
he accepted the challenge
n.NounA call to prove or justify something.
a challenge to the legality of the banning order
n.NounExposure of the immune system to pathogenic organisms or antigens.
recently vaccinated calves should be protected from challenge
v.VerbDispute the truth or validity of.
it is possible to challenge the report's assumptions
v.VerbInvite (someone) to engage in a contest.
he challenged one of my men to a duel
v.VerbExpose (the immune system) to pathogenic organisms or antigens.
The animals were not challenged with antigen after sensitization as the aim was to study the biochemical changes due to sensitization alone.