A

advise
A request for an asynchronous notification that a period of time has elapsed.
alpha
The measure of a pixel's opacity. A pixel with a maximum alpha value is opaque, one with a value of zero is transparent, and one with an intermediate value is translucent.
application notification
An event that the application retrieves from the event notification queue.
asynchronous reader filter
A file source filter that does no parsing on its own, but simply reads data from a media file.
ATR
Audio tape recorder.