From Longman Dictionary of Contemporary Englishhay feverˈhay ˌfever noun [uncountable] MIa medical condition, like a bad cold that is caused by breathing in pollen (=dust from plants)
Examples from the Corpus
hay fever• The treatment is effective for a wide range of illnesses as well as for allergies and hay fever.• The Liberal set-back in 1895 cost him his seat, and his chronic hay fever directed him to an urban constituency.• Medical treatment for hay fever is now much better than it used to be.• He was, however, often racked by asthma and suffered much from hay fever.• Our 4-year-old daughter is sneezing like she has hay fever.• Children can have hay fever, and despite the name, spring is not an uncommon time for its symptoms to appear.• Student B immediately slams it shut, complaining bitterly of hay fever. 