Alpha (or Significance Level) is the maximum allowed probability of committing Type I error in hypothesis.
Beta is the maximum allowed probability of committing Type II error in hypothesis.
An application-oriented question on the topic along with responses can be seen below. The best answer was provided by Aritra Das Gupta on 8th Oct 2020.
Applause for all the respondents - Nilesh Akre, Aritra Das Gupta, Sanat Kumar