What's the difference between "defence" and "defense"?

Question

Two different spellings, are they the same thing? What is the difference if they're not.

Is one American and the other British?

Answer 1

Concise write-up from Wikipedia. Pretty much says it all.

Nouns ending in -ce with -se verb forms: American English retains the noun/verb distinction in advice / advise and device / devise (pronouncing them differently), but has lost the same distinction with licence / license and practice / practise that British spelling retains. American English uses practice and license for both meanings. Also, American English has kept the Anglo-French spelling for defense and offense, which are usually defence and offence in British English; similarly there are the American pretense and British pretence; but derivatives such as defensive, offensive, pretension, pretentious are always thus spelled in both systems.

Commonwealth usage. Canadian English generally follows British usage for licence/license, defence, and offence and American usage for practice; both pretence and pretense are found. Rest of the Commonwealth as per the UK.

Answer 2

Defence = English
Deense = American

Answer 3

"Defence" is a British spelling, and "defense" is an American spelling.

Many British spellings replace the American English "-se" with a "-ce." Many British spellings also replace the American English "-ize" with an "-ise."

Answer 4

defence is British and defense is American English.
both pronounced the same.

Answer 5

Defence is English and defense is American.

The American spelling comes from the French word "défense".