'Cold sore' definitions:

Definition of 'cold sore'

noun

Caused by herpes simplex virus type 1 (HSV-1) [syn: oral herpes, herpes labialis, cold sore, fever blister]

From: GCIDE

Cold \Cold\, n.
1. The relative absence of heat or warmth. [1913 Webster]
2. The sensation produced by the escape of heat; chilliness or chillness. [1913 Webster]
When she saw her lord prepared to part, A deadly cold ran shivering to her heart. --Dryden. [1913 Webster]
3. (Med.) A morbid state of the animal system produced by exposure to cold or dampness; a catarrh. [1913 Webster]
Cold sore (Med.), a vesicular eruption appearing about the mouth as the result of a cold, or in the course of any disease attended with fever.
To leave one out in the cold, to overlook or neglect him. [Colloq.] [1913 Webster]