/at"euh pee/ , n.
an allergy, involving an inherited immunoglobulin of the IgE type, that predisposes a person to certain allergic responses, as atopic dermatitis.
[ 1920-25; atopía extraordinariness, equiv. to átop ( os ) out of place, unusual (see A- 6 , TOPO-) + -ia -Y 3 ]