What does accumulation mean?
The definition of accumulation
Ac*cu`mu*la”tion, n.
Etym: [L. accumulatio; cf. F. accumulation.]

1 The act of accumulating, the state of being accumulated, or that which is accumulated; as, an accumulation of earth, of sand, of evils, of wealth, of honors.
2 (Law)
The concurrence of several titles to the same proof. Accumulation of energy or power, the storing of energy by means of weights lifted or masses put in motion; electricity stored.

— An accumulation of degrees (Eng. Univ.), the taking of several together, or at smaller intervals than usual or than is allowed by the rules.