Licence, defence and offence are three words of Latin origin that frequently appear in legal translations and doubts sometimes arise as to how these terms should be spelt, since they can also be written as license, defense and offense. The differences can be explained in terms of verbs and nouns, and whether we are using standard UK English or standard US English.
In UK English, the accepted spelling is licence for the noun and license for the verb (although according to the Oxford English Dictionary, licence is also an acceptable variant spelling for the verb). In US English, both the noun and the verb are spelt licence.
Concerning the other two terms, the transatlantic divide is also to blame but the other way round: in UK English the accepted spelling is defence and offence, while in US English the preference is for defense and offense.