What are the examples of nouns that don't have a plural form?

Answer 1

Uncountable nouns are singular and usually have no plural form. Of course, there are exceptions, but for the most part uncountable nouns are singular. Some examples of uncountable nouns are:

• water, tea, coffee, milk, oil
• bread, butter, cheese, meat
• air, steam, smoke, smog, pollution
• rice, flour, sugar, salt, pepper
• luggage, furniture, traffic, money, homework, mail
• happiness, love, honesty, knowledge, peace, music, experience
• English, French, Spanish
• aluminum, copper, oxygen, hydrogen
• water, soil, sand, concrete
• slang, vocabulary
• art, philosophy, law, science
• soccer, football, Chess
• weather, thunder, rain, snow, darkness

A notable exception is that the plural form for food and substances is reserved for 'types of' or 'kinds of'; for example:

• ...a variety of foods such as flour, meat, rice, milk, etc.
• ...a menu of teas including black, green, jasmine, oolong, etc.
• ...some properties to consider when selecting concretes are water content and sulfate resistance.
• ...a number of sands are used in construction, very fine, fine, medium, coarse, and very coarse.

Answer 2

Some examples of nouns that don't have a plural form include "furniture," "information," "advice," and "jewelry." These are considered uncountable nouns because they are already plural in nature or represent a singular concept that can't be counted.