Human-readable refers to a representation of information that can be naturally read by humans. In most contexts, the alternative representation is data primarily designed for reading by computers. The numerals that commonly accompany a UPC barcode are a human-readable form of the information present in the barcode. In the case of barcodes used in stores, laws frequently mandate that a human-readable price be displayed with the merchandise, rather than relying solely on the machine-readable barcode and price disclosure only at the point of sale.
In computing specifically, the phrase human-readable refers to data shown in a format easily read by most humans—normally as ASCII- or Unicode-encoded text, as opposed to binary data. Note that any data format at all can be parsed by a suitably-programmed computer; reasons for choosing binary formats over text formats usually center on issues of storage space (a binary representation usually takes up fewer bytes of storage) and ease of reading back into a computer program (less parsing is necessary). However, with the advent of well-specified, structured markup languages such as XML, and the decreasing costs of data storage, compromises between human-readability and machine-readability are now more feasible than they were in the past. However, usually this kind of data compresses very well with data compression schemes and often this data gets compressed for transmission or storage (see OpenDocument format or transmission compression in ITU-T's V.x modem standards, for example), thereby creating binary data.