Learn Spanish (Latin America): El cojín está sobre el sillón.

In Spanish, en can mean 'in' or 'on'. If you want to be specific that something is resting on or on top of a surface, you can use sobre or the complex preposition encima de. In this sentence, sobre el sillón and encima del sillón mean the exact same thing and are completely interchangeable!

Why is it está instead of es?

We use estar (conjugated here as está) to talk about physical location. Even if the cushion is permanently kept on that armchair, stating where something is located requires estar, not ser.

What is the difference between a sillón and a silla?

A silla is a standard, upright chair (like a dining room chair). A sillón is a larger, more comfortable armchair or lounge chair. The ending -ón is often added to words in Spanish to indicate that something is bigger!

Why do the words cojín and sillón have accent marks?

In Spanish, words that end in the letter 'n' naturally put the spoken stress on the second-to-last syllable. Because cojín and sillón are stressed on their final syllables instead, they need those written accent marks to show that they are breaking the normal pronunciation rule.