Paprika and Red pepper

Paprika noun - Plant bearing large mild thick-walled usually bell-shaped fruits; the principal salad peppers.

Red pepper and paprika are semantically related. In some cases you can use "Red pepper" instead a noun "Paprika".

Red pepper noun - Ground pods and seeds of pungent red peppers of the genus Capsicum.

Paprika and red pepper are semantically related. You can use "Paprika" instead a noun phrase "Red pepper".