'Beside' means 'next to' 'The house beside the sea' Besides can be a preposition or an adverb. As a prepostion it means 'in addition to' or 'apart from'. 'What are you studying besides English?' (in addition to) 'Who was there besides John?' ( apart from). As an adverb besides means 'as well' or 'furthermore'. 'There is enough for us and all our friends besides.' If used wrongly you can change the meaning of a sentence. 'Who was there sitting at the table beside/besides John?' beside= next to. besides= apart from!

beside = ở ngoài besides = ngoài... ra As you can see, they're two different words.