As far as I know, an API is an programming ~interface~.

[Interface]
A noun describing a connection between two dissimilar devices or COM objects, such as Automation clients and servers. A common phrase is user interface, meaning the "connection" between the display-keyboard combination and the user.

SDK is a development ~kit~.

[Kit]
A set of articles or implements used for a specific purpose.



I think they are clearly two completly different things, and the terms are very broadly abused.


You can have a Win32 API which is the connection between the code and windows. And then you have the DirectX SDK which is a set of functions, that uses the Win32 (and directX?) API.

[edited by - dreq on May 27, 2004 9:59:34 PM]