What is the meaning of Only?

Alone in a category.

Singularly superior; the best.

Without sibling; without a sibling of the same gender.

Mere.

Without others or anything further; exclusively.

No more than; just.

As recently as.

Emphasizing something that is just or necessary.

Used to express surprise or consternation at an action.

Introduces a disappointing or surprising outcome that renders futile something previously mentioned.

Above all others; particularly.

Under the condition that; but. (clarification of this definition is needed)

But; except. (clarification of this definition is needed)

An only child.

Source: wiktionary.org