<p>Is "all" singular or "plural"?</p>
<p>depends on the context.</p>
<p>Akula123 is right. It depends on the context. For example.
If you have countable nouns in your sentence then all is plural. All potatoes are good.
If you have uncountable nouns such as water then it is singular. All water is blue.
Just an example don’t judge it.</p>