Design
Design is the creation of a plan or convention for the construction of an object, system or measurable human interaction (as in architectural blueprints, engineering drawings, business processes, circuit diagrams, and sewing patterns). Design has different connotations in different fields (see design disciplines below). In some cases, the direct construction of an object (as in pottery, engineering, management, coding, and graphic design) is also considered to use design thinking.
Sound
In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.
Sound Design
Sound design is the art and practice of creating sound tracks for a variety of needs. It involves specifying, acquiring or creating auditory elements using audio production techniques and tools. It is employed in a variety of disciplines including filmmaking, television production, video game development, theatre, sound recording and reproduction, live performance, sound art, post-production, radio and musical instrument development. Sound design commonly involves performing (see e.g. foley) and editing of previously composed or recorded audio, such as sound effects and dialogue for the purposes of the medium. A sound designer is one who practices sound design.
Video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media.
Design
This is exactly the meaning of design: the conflict between form and content, form being the problem. [...] It is the coming together of form and content that is the realization of design.
Paul Rand (2008), Conversations with Students p. 32
Design
Good design is also an act of communication between the designer and the user, except that all the communication has to come about by the appearance of the device itself. The device must explain itself.
Donald Norman (2002), The Design of Everyday Things, Introduction to the 2002 Edition
Sound
Doctor: It plays music. What's the point of that? Oh, with music, you can dance to it, sing with it, fall in love to it. Unless you're a Dalek of course. Then it's all just noise.
Doctor Who Evolution of the Daleks (2007), written by Helen Raynor.