Resolution, in simplest terms, means the fineness of detail or how fine the details are. For example, when talking about display devices such as laptops, mobile phones, television or tablets, we talk about a resolution of 1024 × 768 or 640 × 380, etc. What we are really referring to is how many pixels of data can be displayed in each direction. The more pixels, the finer will be the details, the higher will be the resolution and thus better our viewing experience will be. When we talk about optical devices such as microscopes or binoculars, we are referring to the ability of the device to differentiate between fine details of the sample or object. Higher resolution will simply mean that the microscope will be able to differentiate between finer details of the object.
Hope this helps.