Learn Portuguese (Portugal): O prato está limpo.

We use está (from the verb estar) for temporary states or conditions. A plate being clean is a temporary state because it will get dirty when used! If you used é (from the verb ser), it would imply that being clean is a permanent, built-in characteristic of the plate.

Why does limpo end in -o?

Limpo is an adjective (a describing word). In Portuguese, adjectives must match the gender of the noun they describe. Since prato is masculine (which we can also see from the masculine word for "the", O), the adjective takes the masculine ending -o. If we were describing a feminine noun, like a casa (the house), it would be A casa está limpa.

If I want to say "The plate is VERY clean", do I use muito or muita?

You would say O prato está muito limpo. This is a great detail to notice for your current lesson! When muito is used to mean "very" (describing an adjective), it never changes its ending. It only changes to match the noun (like muitos pratos) when it means "many" or "a lot of".

Does prato mean the physical plate, or the food "dish" you eat?