I found the following claim in a technical book:
"The word raster id derived from the Greek word rustum (rake), owing to the resemblance of a raster to the pattern left on newly raked sand."
I must confess that I can't read enough Greek for even to be able to look the word up in a dictionary, that's why I request your help. I'm aware of the Latin noun "raster" or "rastrum" (rake), but "rustum" doesn't sound very Greek to me. If you could help me either to confirm or deny the claim, I would greatly appreciate it. Thanks!