dave
n. countable B1 Intermediate US //ˈdeɪv// dave
n. a common male name, short for David. In some parts of the UK, people also use it as a friendly way to address a man they don't know.
n. a masculine given name, functioning as a diminutive of David. In specific British dialects, it serves as a generic informal vocative for a male peer.
My friend Dave is coming over for dinner tonight.
The plumber introduced himself as Dave and began inspecting the leaking pipes in the kitchen.
While David remains the formal choice for legal documents, he prefers the more approachable Dave in all professional and social correspondence.
Usage
When used as a proper noun, it is capitalized; as a generic dialectal address, it remains informal.