Fillet
2 of the 6 encyclopedias on this shelf carry an entry for Fillet. Both are reproduced below, so you can see where they agree and where they differ.
The Encyclopedia of Founding (1892)
A rounded corner on a mould. There is less danger of shrinkage flaws when corners are filleted. Flexible metallic filleting, any size required, may be obtained at a nominal figure, so that no pattern need be left without. When fillets are left to be carved off by the moulder it costs twice the amount for labor, and, unless the operation is performed by a good mechanic, the result is invariably a botched job. Filling in.--Setting the inside courses of bricks by the loam-moulder. In heavy walling and solid cores the faces or outer courses are built strong, but the filling-in courses are set wide apart and the spaces filled with fine cinders to lead away the gases. This is a very common term in a foundry. Placing sand inside a flask or any other receptacle, as a riddle, sieve, etc., is usually called filling in. See BRICKING UP.
Collier's New Encyclopedia (1921)
in ordinary language, a band of metal, linen, or ribbon worn round the head. Also the fleshy part of the thigh; applied most commonly to veal. Also portions of meat or fish removed from the bone and served either flat or rolled together and tied round; the term is specially applied to the under-cut of the sirloin of beef, served whole or cut into steaks, and to slices of flat-fish removed from the bone. In anatomy, a collection of fibers passing upward from the anterior columns of the spinal cord. Also a similar bundle of fibers in the corpus callosum. In architecture, a small flat face or band used principally between moldings to separate them from each other in classical architecture; in the Gothic, Early English, or decorated styles of architecture, it is also used on larger moldings and shafts.
What Has Changed in the Last Century
The Founding encyclopedia's advice from 1892 still holds: a rounded internal corner really does reduce shrinkage defects, and today the fillet radius is a standard concern in casting and machining design, with "fillet" now also the name of the command that rounds an edge in almost every CAD program. Wax, leather and flexible metal filleting strips are still sold for pattern-making, though patterns themselves are increasingly 3D-printed with the fillets built in. Collier's culinary and architectural senses in 1921 are unchanged, fish and beef are still filleted and a fillet still separates classical mouldings. The one term that has fallen away is the anatomical one: the fibre bundle Collier's called the fillet is now almost always called the lemniscus, as in the medial lemniscus.
Written for this edition, 2026.