(countable) An accumulation of something, is a number or amount of it that has come together over time.
The failure to pump leads to an accumulation of blood in the heart.

There was an accumulation of dirt on the part of the floor people were walking on.
(uncountable) Accumulation is the process of bringing things together.
The process of salt accumulation in the soil speeds up under poor watering conditions.

Private investment helped to boost capital accumulation.

Noun