STRAIN (through O. Fr. straindre, estraindre, mod. étreindre, from Lat. stringere, to draw tight, related to stress, stretch, string, &c.), to draw out, extend, stretch, especially with the idea of great effort or beyond measure or limit; hence, from the idea of pressure or constriction, to separate coarser matter or light solids from a liquid by pressure through a “strainer,” which may be either a sieve or a colander (Lat. colare, to strain), a metal vessel with perforations in the bottom. Another type is the filter (q.v.). Straining can also be effected by means of cloths, and the name strainer is used of a coarse open cloth usually of flax; a coarser cloth of a more open texture is technically known as “screw.”
For “strains” and “stresses” in physics see Mechanics; Elasticity and Strength of Materials.