|1.||[ noun ] something or someone that causes anxiety; a source of unhappiness|
|Synonyms:||worry concern vexation|
"New York traffic is a constant concern" "it's a major worry"
|Related terms:||negative_stimulus business burden bugaboo worry concern worry|
|2.||[ noun ] (medicine) pain in the head caused by dilation of cerebral arteries or muscle contractions or a reaction to drugs|
|Related terms:||ache tension_headache migraine sinus_headache sick_headache histamine_headache|