A baseball cap is a type of soft cap

Cap

A cap is a form of headgear. Caps have crowns that fit very close to the head and have no brim or only a visor. They are typically designed for warmth and, when including a visor, blocking sunlight from the eyes...

 with a rounded stiff brim. The front of the cap typically contains designs or logos

Logos

' is an important term in philosophy, psychology, rhetoric and religion. Originally a word meaning "a ground", "a plea", "an opinion", "an expectation", "word," "speech," "account," "reason," it became a technical term in philosophy, beginning with Heraclitus ' is an important term in...

 of sports teams (namely baseball

Baseball

Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...

 teams), (or names of relevant companies, when used as a commercial marketing technique). The back of the cap may be "fitted" to the wearer's head size or it may have a plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

, Velcro

Velcro

Velcro is the brand name of the first commercially marketed fabric hook-and-loop fastener, invented in 1948 by the Swiss electrical engineer George de Mestral...

, or elastic

Elastomer

An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...

 adjuster so that it can be quickly adjusted to fit different wearers.

The baseball cap is a part of the traditional baseball uniform

Baseball uniform

A baseball uniform is a type of uniform worn by baseball players. Most baseball uniforms have the names and uniform numbers of players who wear them, usually on the backs of the uniforms to distinguish players from one other. Baseball shirts , pants, shoes, socks, caps, and glove are parts of...

 worn by players, with the brim pointing forward to shield the eyes from the sun.