Binoculars or field glasses ?
They’re different things. Binoculars have three lenses while field glasses have only one lens.
Sandpaper or glasspaper ?
Again different products. In the olden days abrasive sheets were made with tiny bits of glass but they aren’t any more. Glasspaper is an outdated term.
Sitting room or living room ?
Sitting room. Because it’s for sitting. I have a separate room for casual use.
Cutlery or irons ?
Cutlery. Irons is a slang word used colloquially in certain areas.
Dining table or dinner table ?
Dining table. It’s only a dinner table (or breakfast table etc) in big houses where they have separate tables for each meal. My table is used for multiple meals so I use the generic name “dining table”.
Footpath or pavement (I know, they're not necessarily the same thing) ?
Different things. A pavement is paved and usually beside a road. A footpath is for walking and not usually paved.
Lead or leash ?
English vs American. British people say lead.
Glass or tumbler ?
A tumbler is a type of glass. You wouldn’t just ask for a glass, you’d ask for a wine glass or a shot glass or a tumbler etc.
Mug or beaker ?
Different things. A mug is a heavy ceramic cup with a handle. A beaker has no handle and is either glass or plastic.
Tea or dinner (or supper) ?
Different meals at different times. Dinner is the biggest meal of the day regardless of the time at which it’s eaten. Tea is a meal at 3-5. Supper is 8pm onwards when it’s a small meal and not the main meal of the day.