aka prefix-free, or instantaneous code
A string is a prefix of another string if their first symbols coincide, for some .
A prefix code is a Variable-length code where no codeword is a prefix of another codeword.
(IC 2.6) Prefix codes - remarks and what's next
Any prefix code is uniquely decodable
A prefix code can be represented as a search tree, and is a nice way to think about prefix codes.
The above definition may called left-prefix. There is also the notion of right-prefix. See here
Example to see why prefix codes are faster (in the sense of computational complexity) to decode than other uniquely decodable codes. Prefix codes are decodable in linear time
They satisfy the Kraft inequality