The term mecha (メカ, meka) may refer to both scientific ideas and science fiction genres that centers on robots or machines controlled by people. Mechas are typically depicted as "walker" types of mobile robots.
These machines vary greatly in size and shape, but are distinguished from vehicles by their humanoid or biomorphic appearance and size—bigger than a human. Different subgenres exist, with varying connotations of realism. The concept of Super Robot and Real Robot are two such examples found in Japanese anime. The term may also refer to real world piloted humanoid robots/non-humanoid robotic platforms, either currently in existence or still on the drawing board (i.e. at the planning or design stage). Alternatively, in the original Japanese context of the word, "mecha" may refer to mobile machinery/vehicles (including aircraft) in general, manned or otherwise.