Zinc is a metal — one of the basic elements on the periodic table, symbol Zn. It is a slightly blue-grey silver colour, harder and more brittle than lead, and it melts fairly easily. You meet it in three main ways. First, as a coating: iron and steel rust, so factories dip or spray them with zinc to keep the air and water off. That is the dull, spotted silver you see on buckets, roofing sheets, fence posts, and nails — the process is called galvanising, and the result is often called 'galvanised iron'. Second, mixed with copper it makes brass, the yellow metal in door handles, locks, and trumpets. Third, your body needs a little of it to work properly, so 'zinc' also appears on vitamin bottles and on sunscreen and nappy cream (zinc oxide, the thick white paste that sits on top of the skin instead of soaking in). Zinc is also inside ordinary batteries. In everyday speech people mostly say the word in these last two ways — 'take some zinc' when you have a cold, or 'zinc cream' for the beach. It is an uncountable noun, so no 'a' and no plural: 'a piece of zinc', not 'a zinc'. It can also be a verb meaning to coat something with zinc, but that is a technical use you rarely need.