In the United Kingdom, a "quarter" is a term commonly used in the context of weight or mass, especially in agricultural and trade settings. A "quarter" in the UK refers to a quarter of a hundredweight (cwt).
In the United Kingdom:
1 quarter (UK) = 28 pounds (lbs)
So, when you see "quarter" used in the context of weight or mass in the UK, it generally means 28 pounds. This term is frequently used in the sale and trade of agricultural products and livestock, where quantities are often expressed in multiples of quarters. It's important to note that the UK quarter is different from the US quarter, which is 25 pounds.
A "slug," in the context of mass, is a unit of measurement primarily used in the United States customary and British imperial systems. It is not a widely used unit and is considered somewhat archaic. The slug is used to measure mass and is defined as the mass that accelerates at a rate of one foot per second squared (1 ft/s²) when a force of one pound-force (1 lbf) is applied to it. In other words, a slug is the mass that results in an acceleration of 1 ft/s² when a force of 1 lbf is applied to it.