Semiotics, loosly speaking, is the study of signs. Simple enough. What becomes difficult is defining what a ‘sign’ actually is.
When we think of signs we think of the things on the left there don’t we? We think of something visual like a signpost. But, ‘signs’ are made up of many different components - words, sounds, body language and context - all of which combine to create a visual language which help us understand something, be that the way to the beach, or if somebody doesn’t really like us the first time we meet them.