This document discusses audio and its use in multimedia. It defines audio as any recorded voice, music, or both. Audio can convey meaning, provide different learning strategies for different learners, add a sense of realism, and direct attention to important events. It then discusses specific audio terms like volume, frequency, sampling, sample size, channel, sampling rate, and file size calculation. Finally, it outlines the importance of audio for education, noting it can provide student feedback, serve as evidence for activities, and allow recorded lectures and live online discussions to facilitate distance learning.