These 2 words are pronounced in exactly the same way -/həʊl/, but as you can see, they are spelt differently and they mean different things.

• whole is an adjective = entire, complete
• (a) hole  is a noun= an opening or a hollow place in something

In the picture:

The only source of natural light, that illuminates the whole interior of the Roman Pantheon is a central hole at the top of the dome called the Oculus.

= Jedini izvor prirodnog svetla koji osvetljava celu unutrašnjost rimskog Panteona je otvor u centru na vrhu kupole koji se zove Okulus.

whole – ceo, čitav (pridev)

a hole – rupa, otvor (imenica)