Differences between british and american spelling

Most dictionaries include both spellings and will make note of the two spellings. Usually the differences are noted in one of two ways:

In many US dictionaries the difference is included in the headword with the variation in parentheses:

For example colo(u)r

In British Dictionaries, the Dictionary makes note of the difference in brackets immediately after the headword:

For example watch, plural watches; glass, plural glasses

The table provides a list of the main differences between British and American spelling:

-our (honour)
-re (centre)
-ogue (dialogue)
-ence (defence)
-ise 1 (recognise)

-or (honor)
-er (center)
-og (dialog)
-ense (defense)
-ize (recognize)

American English spelling sometimes does not double the consonant at the end of a word, while British English spelling does, especially when the consonant is an 'l'.
For example travel, traveller, travelling (British) and travel, traveler, traveling (American)