HSV-I, also known as Herpes Simplex Virus Type 1, is a common viral infection that causes cold sores around the mouth and lips. There are several synonyms for HSV-I, including oral herpes, fever blisters, or herpes labialis. These terms describe the same virus, but with varying degrees of specificity. The term oral herpes specifically refers to the virus's presence in the mouth area, while fever blisters describe the appearance of cold sores. Herpes labialis refers to the location of the infection, the lips. Regardless of which term is used, HSV-I is a contagious virus that can be spread through close personal contact, including kissing or sharing utensils.