From Longman Dictionary of Contemporary Englishmagnifying glassˈmagnifying ˌglass noun [countable] DTa round piece of glass with a handle, used to make objects or print look bigger → magnify
Examples from the Corpus
magnifying glass• Use of a magnifying glass may be helpful in examining and repairing wounds.• And Rathbone would be on the case, with his bloodhound and magnifying glass.• By squinting or using a big magnifying glass.• When the New Testament is put under the detective's magnifying glass, several whodunnits emerge.• Fujisaki did give the jurors the magnifying glass they requested.• One should pass the magnifying glass over to science; the eyes are sufficient to appreciate the beauties of the landscape. 