What is the difference between pottery ceramics?
No real difference. It's all 'ceramics' due to 'pottery' being made from ceramic material. However, the word ceramics will cover many aspects of the craft, including industrial uses.
with pottery we usually refer to useful household items items like mugs, plates, vases, bowls which are made from ceramic material. The term ceramics includes pottery, but also non-functional items and it can include any artifacts made from ceramic material - including dental inlays or insulators, semiconductors or even building materials like bricks or roof tiles. While the origin of the word ceramics was pretty much the same as pottery it has come to include a much wider range of products.