Communication design is the practice of planning and shaping a message in content, form and delivery. Communication designers craft effective and expressive ways to share ideas with others, using an approach focusing on both problem-solving and persuasion. It is every piece of design that is meant to communicate with somebody, like street signs, clocks, logos etc…
Communication design is a both a broad term and field. It potentially encompasses a number of design practices, including information design, information architecture, advertising and marketing.