Definition
A mass noun (also called an uncountable noun) refers to something that cannot be easily counted because it's seen as a continuous substance or entity. It usually doesn't have a plural form without adding a unit of measurement. Examples include 'water,' 'air,' 'sand,' 'rice,' and 'information.' They are perceived as a whole, not as individual units. You wouldn't say 'one water' but rather 'a glass of water.' The key is that it is typically a continuous substance.