accumulation
This word carries a sense of slow, steady growth rather than a sudden burst. It often suggests a buildup that happens almost unnoticed until the total volume becomes significant or overwhelming. While it can be neutral, it frequently leans toward a negative connotation when describing things that shouldn't be there, such as dust or debt.
In technical or financial contexts, it describes a strategic phase of gathering resources. This contrasts with terms like collection, which implies a curated or intentional set, whereas accumulation focuses on the sheer mass or quantity of the material gathered.
Countable when referring to a specific instance of buildup, such as a snow accumulation of five inches. Uncountable when referring to the general process of gathering, such as the accumulation of knowledge.