Is there more than one notion of algebras?

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I know that an algebra is an algebraic structure, that can be seen as a vector space with a multiplication operation or as a ring with a vector space structure. However, in measure theory we define an algebra as a collection of subsets closed under finite unions and intersections.

My question is: Are these "algebras" related or do they have anything else in common except their name?

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Yes, this is the same notion. Note that an algebra is also closed under complement and contains the whole set and the empty set.

If ${\cal A}$ is an algebra of subsets of some set $X$, we can define on it two operations: the symmetric difference $\Delta$ and the intersection $\cap$. Note the relations between the following indicator functions: $$ {\bf 1}_{A \Delta B}(x) = {\bf 1}_A(x) + {\bf 1}_B(x) \ \ \hbox { mod } 2, $$ $$ {\bf 1}_{A \cap B}(x) = {\bf 1}_A(x) {\bf 1}_B(x). $$ So we have an explicit injective morphism between the algebra $\cal A$ endowed with the two operations $\Delta$ and $\cap$ and the algebra of functions from $X$ to ${\bf Z}/ 2{\bf Z}$ endowed with $+$ and $\times$. It is given by $$ \matrix{{\cal A} & \mapsto & {({\bf Z}/ 2{\bf Z})}^{X} \cr A & \mapsto & {\bf 1}_A \cr} $$ As a result, $\cal A$ is isomorphic to the image of this morphism as an algebra.