A mortarboard is a special type of cap worn with academic regalia at graduations and in certain academic settings. Because it has an extremely distinctive appearance, these caps are often linked in the public eye with the academic world and with the celebrations associated with graduation. They have also historically been linked with the teaching profession, a throwback to an era when instructors wore full academic regalia while teaching.
A classic mortarboard consists of a cap that is attached to a hard, flat square of material. Typically, a tassel is worn with it, with the tassel being attached with a button or tab in the middle of the square section. Depending on the design, the cap may be soft or hard, and it may have laces or elastic to ensure a snug fit, as a properly fitting one should be tight.
Traditionally, the board is positioned so that it is aligned to be parallel with the ground, while the bulk of the cap rests on the back of the head. Depending on regional traditions, the positioning of the tassel may be important; sometimes, the location indicates whether or not the wearer has graduated, or what level of education the wearer has completed.
Classically, mortarboards are designed in the same color as the rest of the wearer's academic regalia, so they are typically black. In the case of colored regalia, the cap may be the same color as the gown, or worn in a contrasting color to create a coordinated look that reflects the school colors of the graduate. The tassel's colors may be matched to the school colors, or they may reflect the discipline the student studied.
The origins of this headgear are quite old. In Roman times, a skullcap much like the modern mortarboard was worn, and such caps were also worn by Muslim scholars in the Middle East. By the Middle Ages, mortarboards were worn by members of some holy orders, which explains how they entered the educational system in Europe; most students were also members of religious orders in the Middle Ages, when the cap flourished.
This cap goes by a number of alternate names, including corner cap, in a reference to the four corners of the square; trencher; or square cap. The name is actually a slang term, in reference to the easily carried boards used by masons to store mortar to work with as they move along on a project.