Immediately after is a phrase that can be used to describe something that happens right away or without delay. It can be broken down into three words: UPON, NEXT, and ASSOONAS. UPON is a preposition that means 'at the time of' or 'in response to'. NEXT is an adjective that means 'immediately following in time or order'. ASSOONAS is an adverb that means 'as soon as possible'. Together, these three words form the phrase 'immediately after', which is used to describe something that happens without delay.