Linked from
The 16 pages that link to Measurable function, each with the reason it gives.
Lebesgue integralBroader topic: Measurability ensures the function's level sets can be measured.
Lp spaceRelated: Only measurable functions are eligible for the integral defining Lp.
Radon–Nikodym theoremRelated: The density supplied by the theorem must be measurable.
Tonelli's theoremNarrower topic: Measurability is one of the theorem's essential hypotheses.
Random vectorRelated: Measurability makes probabilities of vector-valued events well-defined.