n A structure made of connected strands of metal, fiber, or other flexible/ductile material, with evenly spaced openings between them.
n The opening or space enclosed by the threads of a net between knot and knot, or the threads enclosing such a space.
n A measure of fineness (particle size) of ground material. A powder that passes through a sieve having 300 openings per linear inch but does not pass 400 openings per linear inch is said to be -300 +400 mesh.