>[otherwise](http://www.oxforddictionaries.com/definition/english/otherwise) = (adverb)
1. In circumstances different from those present or considered; or else:

>[or else](http://www.oxforddictionaries.com/definition/english/or-else?q=or+else) = (What part of speech???) 1.1. In circumstances different from those mentioned:

Does the semicolon definition 1 for 'otherwise' imply that these two are synonyms? What are the similarities and differences? Also, what part of speech?