The caffeine content of coffee varies greatly, depending on the beans, how they're roasted, and other factors, but the average for an 8-ounce cup is about 100 milligrams (mg).
No, 'cat' is a common noun, a word for any cat of any kind. A proper noun is the name of a person, a place, a thing, or a title; for example: Cat Deeley, host of TV series 'So You Think You Can Dance'.
A proper noun often consists of a group of words, some of which are perhaps ordinarily used as other parts of speech. A proper noun becomes a common noun when used as a name that may be applied to any one of a class of objects. An Advanced English Grammar with Exercises George Lyman Kittredge. A common noun becomes a proper noun when used as the particular name of a ship, a newspaper, an animal, etc. An Advanced English Grammar with Exercises George Lyman Kittredge British Dictionary definitions for proper noun Expand