I never hear "scissor" or "pant" or "jean". It's always "scissors", "pants", and "jeans", respectively. Are they considered plural?
Yes, these words only have a plural form and require the verb in the plural. A list of such words would be very long and, to mention just a few:
- glasses (spectacles)
- pajamas, pyjamas
but beware of "maths" and "aerobics" which are always singular.
For a complete list, follow the links:
They are termed as duals : denoting a form of a word indicating that exactly two referents are being referred to.
Consider these : trousers, panties, glasses, binoculars, both, couple, legs, arms, feet, youse, pair etc.
The singular form is commonly used in compound words such as: scissor-hands, spectacle-case etc.
Scissor used in the singular as a verb may not be grammatically wrong.
Words like "jeans", "scissors", "pants" are non-count nouns. Anything that you cannot buy as a single item (I'd like to buy 1 pant, please) or items that can only be counted in terms of "X's of Y" (pairs of pants/bottles of milk/grains of sand) are non-count.
They don't truly exist as singular or plural. However, we generally use plural verbs with them. "My pants are torn" not "My pants is torn."
Yes, they're plural as Centaurus says. You would say "pass me those binoculars", never "pass me that binoculars"* or "pass me that binocular"*. But as Xen2050 points out, many of those can be used with the classifier "pair" ("A pair of binoculars", "a pair of knickers") in which case the head of the noun phrase is the singular "pair", making the entire noun phrase singular.
Beware of a couple of alternative meanings, though. Centaurus has already flagged "glasses" as only always being plural when it refers to the things you wear in front of your eyes - the type of glass one drinks from behaves "normally" as a known. I avoided using "spectacles" in the clarification, though, because that too has another meaning (noteworthy sights) that can be singular. Similarly, "knicker" is (somewhat archaic) British slang for a pound, and as far as I can tell stays the same in singular and plural.
English has a lot of particularities as to numerus (singular and plural). One group of plural nouns are things that consist of two parts. In English grammars these nouns are often called "pair nouns". Such nouns are
trousers, shorts, pyjamas, braces
scissors, tongs, spectacles, glasses, compasses
Verbs after these nouns have plural form and when referring to one object you use "a pair of" as in a pair of trousers.
I would not mix these pair nouns with other nouns used in plural form as clothes, belongings etc.
The Oxford Guide to English Grammar has pair nouns in paragraph 155. In other languages these pair nouns in plural form may correspond to a noun in singular as in German Schere (singular) for scissors.