Define early, mid, late, core, prime, classic part of decade

Early: New decade is developing their identity and may contain old decade’s leftovers. They may also be the start of core or mid part  influences. Novelty of being in a new decade is prominent.  

Mid: New decade has no old decade’s leftovers. Novelty of a new decade wears off. New decade’s identity is established. They may be the start of late part influences, while still containing early part influences. Almost pure or unique part to the decade.

Late: Decade isn’t new anymore. This part shows signs of what’s to come in the upcoming decade. Early part influences are gone, while mid part influences are still around.

Core: The most representative part of a decade. 

Prime: When the decade’s identity is fresh. 

Classic: The most fondly remembered part of a decade.