Moving from the (generally) well-named, well-structured, and well-documented ASP.NET world to SharePoint is daunting on many levels and the terminology differences as you drill down into SharePoint can be confusing. Quite often the SharePoint UI will label a concept one way while the API refers to the same concept with an entirely different term. Unfortunately a lot of this stems from the v2 to v3 transition.
Cory Roth has started putting together a list of these differences but if you’re just starting out there are two very important items worth highlighting:
|UI Term||API Class Name|
My own personal trick to remember this is “a site contains webs”… and really MS, WTF is a web if it’s not the web?!?