B
B*-tree (B star tree)
  A tree in which only the leaves contain whole elements. All other nodes contain keys.
background color
  The color in which the background of a graphic primitive is drawn.
backslash
  The character \. This character is named <backslash> in the portable character set.
balance
  (1) For audio, refers to the relative strength of the left and right channels. A balance level of 0 is left channel only. A balance level of 100 is right channel only. (2) A state of equilibrium, usually between treble and bass.
base class
  A class from which other classes are derived through inheritance. A base class may itself be derived from another base class.
based on
  A relationship between two classes in which one class is implemented through the other. A new class is based on an existing class when the existing class is used to implement it.
binary expression
  An operation containing two operands and one operator.
binary stream
  (1) An ordered sequence of untranslated characters. (2) A sequence of characters that corresponds on a one-to-one basis with the characters in the file. No character translation is performed on binary streams. IBM.
bit field
  A member of a structure or union that contains a specified number of bits.
bit mask
  A pattern of characters used to control the retention or elimination of portions of another pattern of characters.
block
  (1) In programming languages, a compound statement that coincides with the scope of at least one of the declarations contained within it. A block may also specify storage allocation or segment programs for other purposes. I. (2) A string of data elements recorded or transmitted as a unit. The elements may be characters, words, or physical records. T. (3) The unit of data transmitted to and from a device. Each block contains one record, part of a record, or several records.
block statement
  A group of data definitions, declarations, and statements that appear between a left brace { and a right brace } that are processed as a unit. IBM.
boundary alignment
  The position in main storage of a fixed-length field, such as halfword or doubleword, on an integral boundary for that unit of information. For example, a word boundary is a storage address evenly divisible by four. See alignment.
bounded collection
  A collection that has an upper limit on the number of elements it can contain.
brackets
  The characters [ (left bracket) and ] (right bracket), also known as square brackets. When used in the phrase "enclosed in (square) brackets" the symbol [ immediately precedes the object to be enclosed, and ] immediately follows it. When describing these characters in the portable character set, the names <left-bracket> and <right-bracket> are used. X/Open.
breakpoint
  A marker in a program that signals the debugger to stop when execution reaches that point. Code beyond the breakpoint is not executed until further instructions are provided.
break statement
  A language control statement that contains the keyword break and a semicolon. It is used to end an iterative or switch statement by exiting from it at any point other than the logical end. Control is passed to the first statement after the iteration or switch statement.
buffer
  (1) A routine or storage used to compensate for a difference in the rate of flow of data or in the time of occurrence of events when transferring data from one device to another. ANSI. (2) To allocate and schedule the use of buffers. ANSI.
buffer flush
  A process that removes the contents of a buffer.
built-in function
  A function that the compiler automatically puts inline instead of generating a call to the function. Contrast with intrinsic function. IBM.