strainer and filter differences

What is the difference between a strainer and a filter? 

Actually there isn't any since strainer is in reality, a coarse filter. The question is then one of semantics. Generally it is assumed that if the particle to be removed is not cisible to the naked eye, the unit is filtering, and if the particle is visible, the unit is straining. The average human eye can detect a specific particle between 50 and 70 microns. Most people cannot see anything smaller than 325 mesh, or 44 microns. Since 200 mesh is equivalent to 74 microns, a general rule would be that if the csreening device is coarser than 200 mesh it is strainer.