centreless grinding, both plunge and through-feed grinding

Many thanks, bluejay! That makes a lot more sense than my suggestion. I have googled some more and sure enough, the article in Wikipedia has the following to offer:
"Centerless grinding is classified into two types:
Throughfeed grinding - the workpiece is fed into the machine along the work blade
Plunge grinding - the workpiece is placed between the wheels on a work blade and the grinding wheel is plunged into the workpiece."

I'm glad I asked :-))