Final answer:
A sieve with four openings per linear inch is a 4-mesh sieve that is used to determine the size of particles that can pass through it.
Step-by-step explanation:
In the context of sieves, the number of openings per linear inch is commonly referred to as the mesh size or mesh count of the sieve. This measurement is used to determine the size of particles that can pass through the sieve.
In this case, a sieve with four openings per linear inch would be referred to as a 4-mesh sieve. This means that there are four openings (or wires) per linear inch of the sieve, and it is used to sift particles that are larger than the openings but smaller than the actual mesh size.
For example, if you have a 4-mesh sieve and you pass a material through it, only particles that are smaller than the 4-mesh size will pass through, while bigger particles will be retained.