Q From Norbett Mintz: The designation of robes for academic dress clearly comes from its origin with the clergy in the Middle Ages. But what about mortarboards? The best I could find was its origin in the 12th or 13th century clergy cap, but that was not square-shaped. Does mortarboard refer to the guilds or is its origin more ancient?
A The academic cap often called a mortarboard is quite ancient, but that word for it only dates from the middle of the nineteenth century (a less slangy way to identify it is to call it a square). The literal mortar board is the wooden plate, usually with a handle underneath, on which bricklayers carry small amounts of mortar (also sometimes used for a larger board placed on the ground on which a stock of mortar is kept ready for use). A similar tool is used by plasterers, but they usually call it a hawk.
What seems to have happened is that the similarity in shape between the brickie’s board and the academic cap led some wag, probably at Oxford University, to apply the name of the one to the other. Our first recorded use is in a book of 1853–6, The Adventures of Mr. Verdant Green, an Oxford Freshman by a clergyman named Edward Bradley, who wrote under the pen name of Cuthbert Bede (the names of the two patron saints of Durham, where he went to school). Verdant Green is a sort of undergraduate Pickwick and the book recounts his adventures. This magisterial reprimand by a don appears after one such escapade: “I will overlook your offence in assuming that portion of the academical attire, to which you gave the offensive epithet of ‘mortar-board’; more especially, as you acted at the suggestion and bidding of those who ought to have known better”.
After a slow start, the book became a huge success, selling more than 200,000 copies in the next 20 years. Whether Mr Bradley invented the slang term we may never know, but his book certainly popularised it.