What is SharePoint list?
Any web part in SharePoint that holds content is a SharePoint list.
What is SharePoint library?
A library in SharePoint is essentially a special list, created specifically to store documents. That’s all it is. It is a special web part that already exists in SharePoint (called Document Library) that allows to store documents and has all the functionality around documents (document preview, versioning, check-in/check-out, document approval, file type breakdown, etc.)