Sometimes they are synonyms - in the meaning "in spite of the fact that': Я не могла уснуть, ХОТЯ / ХОТЬ И была уставшей. ХОТЯ In combination with БЫ means " at least": Съешь хотя бы яблоко = Съешь хоть яблоко. But ХОТЬ has so many meanings. Here is a useful link, just type the word you r looking for; if you donot understand russian well enough, let me know - i will try to clear it up for you. http://www.gramota.ru