General

General is a specific Officer rank. However, the term can refer to any General Officer rank.

United Kingdom
General is currently the highest peace-time rank in the British Army and Royal Marines. It is the equivalent of a 4 star rank, and is subordinate only to the Army rank of Field Marshal and the Royal Marines rank of Captain General Royal Marines.

A General's insignia is a crossed sword and baton. This appeared on its own for the now obsolete rank of Brigadier-General. A Major-General has a pip over this emblem; a Lieutenant-General a crown instead of a pip; and a full General both a pip and a crown. The insignia for the highest rank of Field Marshal consists of crossed batons within a wreath and surmounted by a crown.

United States
In the US Army, US Air Force, and US Marine Corps, General is a four-star general officer rank, with the pay grade of O-10. General ranks above lieutenant general and below General of the Army or General of the Air Force; the Marine Corps does not have an established grade above general.

General is equivalent to the rank of Admiral in the other uniformed services. Since the grade of General of the Army and General of the Air Force are reserved for war-time use only, and since the Marine Corps has no five-star equivalent, the grade of general is currently considered to be the highest appointment an officer can achieve in these three services.