Block

The concept of a block as a group or a piece appears in various fields:

A city block is the smallest part of a town enclosed by streets.
A block can also mean an apartment block (Block of Flats in British English).
In the construction (building) industry, a block comprises a shaped piece of masonry.
In philately, a postage stamp block is an attached group of postage stamps.
A block (music) is a separate complete unit that is primarily not developed but instead used in various combinations, these may be contrasted or transformed, and each block may be broken into parts and developed independently.
In programming languages, a block (progamming) forms a subdivision of a program that serves to group related statements, delimit routines, specify storage allocation, delineate the applicability of labels, or segment parts of the program for other purposes.
In data storage, either in primary or on secondary storage, grouped data can occur in units known as blocks or buffer. Compare block size (data storage and transmission).
The word in also used in the martial arts to refer to techniques which prevent an attack from connecting with your body (see blocking techniques)
See also block cipher, block matrix, block size.

Telecommunication

In telecommunication, the term block has the following meanings:

A group of bits or digits that is transmitted as a unit and that may be encoded for error-control purposes.
A string of records, words, or characters, that for technical or logical purposes are treated as a unit. Blocks (a) are separated by interblock gaps, (b) are delimited by an end-of-block signal, and (c) may contain one or more records. A block is usually subjected to some type of block processing, such as multidimensional parity checking, associated with it.