What do the terms Farm, Site, Web, WebApplication refer to in the SharePoint API?

Question

I'm sorry for dumb question but I am very new to Sharepoint 2010 and something is not clear to me.

What do the terms Farm, Site, Web, and WebApplication mean?

I pretty much understand Farm and Site, but what is difference between Web and WebApplication?

This distinction is not clear to me, just like the one for Web Part and Visual Web Part for which I eventually found some explanations.

Answer 1

This should help - "SharePoint Terminology – Farms, Web Front Ends, Web Application and Sites"

Specifically - "what is difference between Web and WebApplication?"

Generally when you see "Web" mentioned in programming terms (SPWeb) it actually means a means what a user calls a site and a "Site" (SPSite) is a site collection.

A Web Application is a unit of organisation inside IIS.

Answer 2

SharePoint: Farm, web application, sites collection, sites and subsites, how to know what to use?
SharePoint Terminology – Farms, Web Front Ends, Web Application and Sites

Answer 3

Microsoft defined here http://technet.microsoft.com/en-us/library/cc263121.aspx

Answer 4

The SPFarm, SPWebApplication, SPSite and SPWeb classes in the SharePoint API have particular meaning when developing customizations.

MSDN does a very good job of defining the meaning of the four terms as used by the classes linked to above, so I won't restate, but summarize starting from the top of the hierarchy.

• A Farm is a configuration object and it's the top level of the container hierarchy in SharePoint. All of the other objects inherit down from one Farm object.
• A Web Application represents an IIS Web Application contained by a Farm.
• The SPSite object represents a collection of SharePoint websites, represented by SPWeb objects. An instance of an SPSite object is more commonly referred to as a Site Collection. A Site Collection depends on a web application and a farm for configuration properties and the IIS web application.
• The SPWeb object represents a SharePoint website. An instance of an SPWeb object is commonly referred to as a SharePoint site or just a site.