I have a very vague recollection of my childhood, but, of course, there are some things that have stayed in my memory.

recollection 是由前缀 re-（表示"重新"）和 collection（收集）组成的复合词。re-表示"再次"，collection来自动词collect（收集），所以recollection字面意思是"重新收集"，引申为"回忆、记忆"的意思。