different from, than or to?

I would have said that "comparison" was the essence of "difference"!

The OED gives an example from Goldsmith:

1. The consuls had been elected for very different merits than those of skill in war.

MrP

I also find a difference in focus between "different from" and "different to":

1. A is different from B.

— focus on A.

2. A is different to B.

— focus on B.

This may be a foible though.

MrP

Usage Note: Different from and different than are both common in British and American English. The construction different to is chiefly British. Since the 18th century, language critics have singled out different than as incorrect, though it is well attested in the works of reputable writers. According to traditional guidelines, from is used when the comparison is between two persons or things: My book is different from (not than) yours. Different than is more acceptably used, particularly in American usage, where the object of comparison is expressed by a full clause: The campus is different than it was 20 years ago. Different from may be used with a clause if the clause starts with a conjunction and so functions as a noun: The campus is different from how it was 20 years ago. ·Sometimes people interpret a simple noun phrase following different than as elliptical for a clause, which allows for a subtle distinction in meaning between the two constructions. How different this seems from Paris suggests that the object of comparison is the city of Paris itself, whereas How different this seems than Paris suggests that the object of comparison is something like “the way things were in Paris” or “what happened in Paris.”

 http://dictionary.reference.com/search?q=different&r=66