IPA: /əˌkjuː.mjʊˈleɪ.ʃən/
KK: /əˌkjuː.mjʊˈleɪ.ʃən/
A large amount of something that has been gathered or collected over time.
The accumulation of snow made it difficult to drive.
Accumulation → It is formed from "ad-" (meaning to) and "cumulare" (meaning to heap or pile up) and the suffix "-tion" (indicating the action or process). The word "accumulation" refers to the process of gathering or piling up things together.
Think of 'heaping up' ('cumulare') things 'to' a place ('ad-') — that's why accumulation means the process of gathering together.