cold sore

noun

: a group of fluid-filled blisters appearing about or within the mouth that are caused by a herpes simplex virus and upon rupturing form crusts

called also fever blister

compare canker sore

Examples of cold sore in a Sentence

Recent Examples on the Web

Inventors also started mixing in soothing or medicinal compounds into lip balms and marketing multi-use balms—for, say, cold sores or acne pain. —Mark Hay, Popular Science, 13 Aug. 2025

Scientists are working to harness the power of the herpesvirus responsible for cold sores in order to treat a deadly cancer: late-stage melanoma. —Emily Kay Votruba, EverydayHealth.com, 18 July 2025

This raises the risk of a host of complications that could impact your belly button, including both bacterial skin infections and viral infections, like warts or cold sores. —Korin Miller, SELF, 11 June 2025

Of the groups studied, 1,507 people with Alzheimer’s also had herpes simplex virus type 1 (HSV-1), which is the most common cause of cold sores. —Khloe Quill, FOXNews.com, 23 May 2025

Word History

First Known Use

1870, in the meaning defined above

Rhymes for cold sore

• abhor
• abor
• adore
• afore
• ardour
• ashore
• backdoor
• before
• bookstore
• candour
• centaur
• claymore

Kids Definition

cold sore

noun

: a group of blisters about or within the mouth caused by a herpes virus

called also fever blister

Medical Definition

cold sore

noun

: a vesicular lesion that typically occurs in or around the mouth, that initially causes pain, burning, or itching before bursting and crusting over, and that is caused by a herpes simplex virus which remains dormant in the body and may be reactivated by a variety of factors (as stress, fever, or sunburn)

called also fever blister

compare canker sore