All current academic dress styles have come to us as adaptations of medieval clothing, both academic and clerical.
Academic regalia are usually composed of three items
the gown
the hood, sash or stole
and headwear such as the trencher cap or mortarboard, the Tudor bonnet or the tam.
The gown is usually black (as originally students were required to wear only sombre colours), gathered into a yoke at the back in "organ pipe" pleats, and reaching past the knees. There is usually a slit for the arms or a closed "bell" sleeve in the case of Master or doctoral gowns.
The hood was originally worn for warmth and to protect the head from sun and rain, often with a cape and/or an extended tail wrapped around the neck as a scarf. Over the centuries the shape has changed considerably and many universities have adopted different forms. The University of Western Australia has adopted the Oxford simple shape for its hood. This consists of a cowl of coloured silk which indicates the discipline being studied, and a liripipe or shaped tail. The cowl can be single coloured or edged with white silk, or other coloured silk, indicating the level of study.
The best known academic headwear is the trencher cap or mortarboard which is generally a hard or folding skull cap, topped by a square board, made of cloth or wool and with a black tassel. The word trencher comes from the archaic word meaning a flat wooden plate or slice of thick coarse bread to use as a plate.
This universal symbol of scholarship was formally adopted by Oxford University in the mid 1500s and has been reintroduced for Bachelor graduates at The University of Western Australia in 2014, after having been previously phased out in the mid 1970s. Higher degrees are often denoted by velvet headwear and/or coloured tassels, as is the case at The University of Western Australia.