Originally posted by Bliss
SLR stands for "Manual Single-lens-Reflex" An SLR camera is one that you can adjust everything manually instead of electronically. What you see in the viewfinder is what you'll get when developed. You can adjust everything by dials, and bottons before you shoot.
Close, but not exact. You are correct in that SLR stands for Single-Lens-Reflex. There are three distinct features in a SLR camera:
(a) One lens is used for both viewing and taking the picture.
(b) The above is facilitated by the fact that the image is reflected by a mirror into a viewfinder when you are viewing the image when composing.
(c) The mirror moves out of the way when the actual picture is taken, allowing the image to reach the backplane where the film resides.
SLR design has nothing to do with the camera being either manual or automatic (I think that's what you meant when you said electronically). The impetus for the SLR design was the benefit of seeing the image exactly as it will be taken, thus eliminating parallax error inherent in rangefinders that were so popular when SLR was first introduced.