The term minicomputer originated in the early 70s to
classifly a type
 of sub $50000 computer that could be purchased by departments (as opposed
 to having to go though corporate DP approval) 
As a data point, the Philips P850 (1971-ish) actually claims to be a
'minicomputer' on the front panel. It's one of the few series of machines
that does IMHO
-tony