What is difference between Servlet and Java Servlet API?

I found definitions of servlet and Java Servlet API everywhere, for example this from oracle :

“The Java Servlet API lets you define HTTP-specific classes. A servlet class extends the capabilities of servers that host applications that are accessed by way of a request-response programming model.”,

but couldn’t find exact definitions of servlet and Java Servlet API, like what they truely are and what is connection between them (if there is any).

I would use some help, thanks. 🙂