A GP is the doctor most people see first: the one in a town or neighbourhood who looks after everyday health — a cough, blood pressure, a child’s ear, a rash that will not go away. The letters stand for general practitioner. “General” here means they are trained in general medicine, not that they are a weaker kind of doctor; though actually, learners sometimes hear “general” and think “not a real specialist.” In the UK they are the specialists of first contact. You register with a GP, you “see your GP,” and if you need a heart doctor or a surgeon, the GP is often the person who writes the letter. The word belongs to British English and to places that follow it (Ireland, Australia, New Zealand, and others). Americans more often say family doctor or primary care doctor, though some know GP too. It is ordinary, slightly institutional English — clinic signs, health-service letters, and daily talk — not slang and not stiff. People also stretch GP to mean the local clinic itself (“I’m at the GP”), which is loose but common.