If you offered to show somebody your "collection" 
of cels....and those TWO cels were, say, Disney 
production cels...well, that would be a pretty 
amazing collection right there!  Wouldn't you say? 
  ^_^

If you want to assign some sort of definition to 
your cel collection, then how about calling it a 
collection when you've established some sort of 
theme or themes?  When somebody can look at your 
cels (whether you have 2 or 200) and see a pattern 
(babes, bishies, action, portraits, a certain 
anime, etc.) then you have a proper collection.  
Until then, you have a random assortment of cels. 
 ;-)

I still recall being a total newbie 2 years ago 
and meeting ix, emika, evilminion, darkamber, 
crackdog, kirins and some others at my very first 
gathering.  I had a handful of cheapie ($5-35) 
Tenchi cels and that's it.  And you *know* what 
kinds of collections those folks have.  Darkamber 
brought BOXES of cels.  But all that mattered was 
that each of us liked what we collected.  ^_^

JP