Grice,

That's kind of like asking the difference between a square and a rectangle. A nano cube is just one particular brand/style of aquarium.

Dry,I knew it was a dumb question with a simple answer.
Oh well,I guess I've reached my quota of asking stupid questions for the month. LOL.
Grice

NANO is latin ,I think for small. They usually use the term when refering to a reef style set up because most reefs are 55gal+. It is reccommended that reefs be taller rather than longer, so instead of makeing say a 10 gal the "standard" size, they make it a cube so it is deeper. I think.LOL

Thanks Woe.
The first things that sprang to mind were Nano-Nano( for those of us who remember Mork ;gosh that makes me a dinasour)and Borg Nano technology (I watch far too many Voyager episodes).
Thanks for helping lift my 'fog'.
Grice