What is the term for alluding to a more formless concept by listing its specific members?
At least in the context of 春夏秋冬 being used to represent the cycle of time, some might call that a "metonym". From The American Heritage Dictionary (on Wordnik):


  n. A figure of speech in which one word or phrase is substituted for another with which it is closely associated, as in the use of Washington for the United States government or of the sword for military power.


"Washington" is often used to represent the US government, though it's really only a place. Maybe in the case of Chinese (or Vietnamese), such phrases are so commonly used that they become lexicalized as the standard means of expressing the concept.