The adverb of *successive*: one after another, in order, without gaps. It describes the verb rather than a noun, so instead of "three successive owners" you get "the house was owned successively by a doctor, a teacher, and a bank".

That example shows what it is really for. When you list things and want the reader to know the list is a time order — this one, then that one, then the next — *successively* does the work in a single word. Without it, "the house was owned by a doctor, a teacher, and a bank" could mean all three owned it together.

It is noticeably more formal than *successive*, and much rarer in speech. You will meet it in history, science writing, and technical description: "the samples were successively heated, cooled, and weighed". In ordinary talk people say "one after the other" or "in turn", and those sound more natural for most students most of the time. Keep *successively* for writing, and use it when the order genuinely matters.