Referring to people according to a single characteristic: "the gray beard" representing an older man or "the long hair" representing a hippie. This leads to bahuvrihi compounds.
Describing a complete vehicle as "wheels", or a motorcycle as handlebars
Referring to people by a particular body part. For example, "head count", "counting noses", or "all hands on deck!", or "eyeballs" observing adverts.
Describing a small portable radio as a "transistor" (though that may simply be an abbreviation for "transistor radio"), or a CRT-based television receiver as "the tube"
Saying bubbles to refer to Champagne or any other sparkling wine
"Arabian sands" to refer the Arabian deserts.