"Belongings" is a plural noun. "Belonging" (without "s") has a different meaning. It refers to a feeling of being accepted in a particular place or with a particular group of people.

"Belongings" is a plural noun.

Robert packed all his belongings in his car and drove away.

Robert packed all his belonging in his car and drove away.

Plural nouns, also known as pluralia tantum (Latin for "plural only"), cannot be used with the article "a". They also take a plural form of a verb, so we say "belongings are", not "belongings is".

Where are your belongings?

Where is your belongings?

Remember, plural nouns require a plural pronoun, such as "they", "those", "these", etc.

Those belongings are not mine.

Other pluralia tantum or plural nouns that are also related to "stuff" are "contents" and "goods".

The term "belonging" (without "s") has a different meaning. We use it to refer to a feeling of being accepted in a particular place or with a particular group of people. "Belonging" (without "s") is an uncountable noun, and therefore takes a verb in the singular.

I think that belonging is like love.

"Belonging" is also the gerund of "belong". You can use this verb when something is in the right place.

Put the book back where it belongs.

We also use it when someone feels comfortable in a particular place or with a particular group of people.

Olivia doesn’t feel that she belongs here.