A shirt is a cloth garment for the upper body (from the neck to the waist). Originally an undergarment worn exclusively by men, it has become, in American English, a catch-all term for a broad variety of upper-body garments and undergarments. In British English, a shirt is more specifically a garment with a collar, sleeves with cuffs, and a full vertical opening with buttons or snaps (North Americans would call that a “dress shirt”, a specific type of collared shirt). A shirt can also be worn with a necktie under the shirt collar.
There are two main categories of fibres used: natural fibre and man-made fibre (synthetics or petroleum based). Some natural fibres are linen, the first used historically, hemp, cotton, the most used, ramie, wool, silk and more recently bamboo or soya. Some synthetic fibres are polyester, tencel, viscose, etc. Polyester mixed with cotton (poly-cotton) is often used. Fabrics for shirts are called shirtings. The four main weaves for shirtings are plain weave, oxford, twill and satin. Broadcloth, poplin and end-on-end are variations of the plain weave. After weaving, finishing can be applied to the fabric.
Many terms are used to describe and differentiate types of shirts (and upper-body garments in general) and their construction. The smallest differences may have significance to a cultural or occupational group. Recently, (late twentieth century, into the twenty-first century) it has become common to use tops as a form of advertisement. Many of these distinctions apply to other upper-body garments, such as coats and sweaters.