In a layman’s term, a noun is generally a name, a content word that is used to refer to anything; a name tag or a label by which something is known; that is, a signifying word.
The definition above virtually describes what a noun is; but you need to know in details, for proper understanding, other ways by which a noun can be easily identified.

Grammatical Category of a Noun
A noun belongs to the grammatical category of words commonly referred to as Parts of Speech or Word Classes. A noun has been generally defined as the name of persons, places, animals or things. You must have used this definition at one time or the other. It could even be the only definition of a noun you know. Never bother, this is very true but there are numerous words that do not belong to any of these categories and they are still classified as nouns. Therefore, the definition of noun as the name of any person, place, animal or thing does not completely capture what a noun is.

Description of a Noun
So then, what is a noun? Rather than provide an overarching definition of a noun or a one-size-fits-all definition, it is expedient to describe a noun by what it does or how it appears – by its form and function. In other words, we will adopt a descriptive perspective to explaining the concept of a noun rather than a prescriptive approach which simply prescribes or defines. There are various ways to describe what a noun is...

Read more: https://akademia.com.ng/what-is-a-noun/

We don't need to click the link, we know what part of speech a word is by the work it does in a sentence. Example, "this is a table", table is a noun here.

"I need a table spoon", table is an adjective here.

Or "I like swimming", swimming is a noun here. (Gerund)

"He is swimming", swimming is a verb here. (Present continuous).

So why should I click the link?

12submarine:
We don't need to click the link, we know what part of speech a word is by the work it does in a sentence. Example, "this is a table", table is a noun here.

"I need a table spoon", table is an adjective here.

Or "I like swimming", swimming is a noun here. (Gerund)

"He is swimming", swimming is a verb here. (Present continuous).

So why should I click the link?

Savage!