The Relationship Between Topological and Measurable Spaces
Remark
Remark. The notion of a measurable space (and of a measurable function) is superficially similar to that of a topological space (and of a continuous function); the topology contains and just as the σ-algebra does, but is now closed under arbitrary unions and finite intersections, rather than countable unions, countable intersections, and complements. The two spaces are linked to each other by the Borel σ-algebra construction.
References
Tao, T. — An epsilon of room-pages from year three of a mathematical blog.pdf, Remark 1.1.3