A large operator symbol representing disjoint union or external direct sum of sets or algebraic structures.
Examples
Disjoint union of sets indexed by natural numbers
\biguplus_{n=1}^{\infty} A_n
Disjoint union of vector spaces
V = \biguplus_{i=1}^{k} V_i \text{ where } V_i \cap V_j = \emptyset \text{ for } i \neq j
Categorical coproduct notation
\biguplus_{\alpha \in I} X_\alpha \cong \coprod_{\alpha \in I} X_\alpha