block / bläk/ • n. 1. a large solid piece of hard material, esp. rock, stone, or wood, typically with flat surfaces on each side: a block of marble. ∎ a sturdy, flat-topped block used as a work surface, typically for chopping food. ∎ (usu. blocks) any of a set of solid cubes used as a child's toy. ∎ (usu. blocks) a starting block: the thrust a sprinter gets when coming out of the blocks. ∎ (also cylinder block or engine block) the main body of an internal combustion engine, containing the pistons. 2. the area bounded by four streets in a town or suburb: she went for a run around the block. ∎ the length of one side of such an area, typically as a measure of distance: he lives a few blocks away from the museum. 3. a building, esp. part of a complex, used for a particular purpose: a cell block. ∎ chiefly Brit. a large single building subdivided into separate rooms, apartments, or offices: an apartment block. 4. a large quantity or allocation of things regarded as a unit: a block of shares [as adj.] block grants. ∎ Comput. a large piece of text processed as a unit. ∎ an unseparated unit of at least four postage stamps in at least two rows, generally a group of four. 5. an obstacle to the normal progress or functioning of something: substantial demands for time off may constitute a block to career advancement. ∎ Sports a hindering or stopping of an opponent’s movement or action. ∎ Tennis a shot in which the racket is held stationary rather than being swung back, esp. a stop volley. 6. a flat area of something, typically a solid area of color: cover the eyelid with a neutral block of color. 7. a pulley or system of pulleys mounted in a case. 8. inf. a person’s head: “I’ll knock your block off,” he said. • v. [tr.] 1. make the movement or flow in (a passage, pipe, road, etc.) difficult or impossible: block up the holes with sticky tape. ∎ put an obstacle in the way of (something proposed or attempted): he stood up, blocking her escape. ∎ restrict the use or conversion of (currency or any other asset). ∎ Sports hinder or stop the movement or action of (an opponent). ∎ Sports stop (a blow or ball) from finding its mark: when driving for a lay-up or leaping to block a shot. ∎ Med. produce insensibility in (a part of the body) by injecting an anesthetic close to the nerves that supply it. ∎ Bridge play in such a way that an opponent cannot establish (a long suit). 2. shape or reshape (a hat) using a wooden mold. PHRASES: have been around the block (a few times) inf. (of a person) have a lot of experience. the new kid on the block inf. a newcomer to a particular place or sphere of activity, typically someone who has yet to prove themselves. on the (auction) block for sale at auction: the original first manuscript for Ravel's Bolero goes on the block today fig. the company put its subsidiary on the block because it did not fit its core business interests. PHRASAL VERBS: block something in 1. mark something out roughly. ∎ add something in a unit: it's a good idea to block in regular periods of exercise. 2. park one's car in such a way as to prevent another car from moving away: he blocked in Vera's minivan. block something out 1. stop something, typically light or noise, from reaching somewhere: you're blocking out my sun. ∎ fig. exclude something unpleasant from one's thoughts or memory. 2. mark or sketch something out roughly. ORIGIN: Middle English (denoting a log or tree stump): from Old French bloc (noun), bloquer (verb), from Middle Dutch blok, of unknown ultimate origin.
1. A collection of data units such as words, characters, or records (generally more than a single word) that are stored in adjacent physical positions in memory or on a peripheral storage device. A block can therefore be treated as a single unit whereby data can be (and usually is) transferred between storage device and memory, using one instruction. Blocks may be fixed or variable in size.
A stream of data to be recorded on magnetic tape is divided into blocks for convenience of handling and particularly of error recovery. (The equivalent on disks is sectors.) Successive blocks are usually separated by interblock gaps and often also by control signals introduced by the magnetic tape subsystem and invisible to the host (see tape format). It is usual but not essential for the block length to be the same for all blocks of data within a volume or at least within a file, though this may not apply to labels; where the end of a file occurs partway through a block, the remainder of the block may be filled with padding characters.
The choice of block length is largely dependent on error management considerations. The minimum length of the interblock gap is defined by the standard for the tape format in use; the maximum length is usually undefined, except that a very long stretch (typically 25 feet) of blank tape is taken to mean that there is no more data on the volume. To avoid wastage of tape the gap written is usually fairly close to the minimum but it may be elongated in some circumstances, e.g. by error recovery actions or to leave space for the editing of a file (which in this context means its replacement by a new version of the same length).
In conventional magnetic tape subsystems the division of data into blocks is carried out by the host. However some buffered tape subsystems, particularly streaming cartridge tape, accept a continuous data stream from the host, and the subsystem itself divides the data into blocks (in this case often called blockettes) in a manner that is not visible to the host. In these subsystems the interblock gap may be very short or absent.
2. In coding theory, an ordered set of symbols, usually of a fixed length. The term is generally synonymous with word or string, but with the implication of fixed length.
3. See block-structured languages.
4. In parallel programming, to prevent further execution of one sequence of instructions until another sequence has done whatever is necessary to unblock it. See also blocked process.
1. Piece of stone, terracotta, etc., prepared for building and bigger than a brick.
2. Rectangular plain element at the bottom of a door-architrave, also stopping the skirt or plinth in Classical architecture.
3. Row or mass of buildings connected together, as in a terrace, set against a street on the front and bounded by other streets, often of mixed use.
4. Most significant building in an architectural composition, e.g. a corps de logis with wings.
5. One of a series of projecting blocks on architraves, columns, or pilasters as in a Gibbs surround: in such cases the architrave, column, or pilaster is said to be banded or blocked. See band.
6. Small triangular piece of timber in the angle between two other timbers, e.g. at the top of two cruck blades.
put one's head on the block put one's position or reputation at risk by proceeding with a particular course of action; with allusion to the block of wood on which a condemned person was formerly beheaded.
See also a chip off the old block.
Hence (or — F. bloquer) block vb. XV; whence blockade XVII.
A segment of a town or city surrounded by streets and avenues on at least three sides and usually occupied by buildings, though it may be composed solely of vacant lots. The section of a city enclosed by streets that is described by a map which indicates how a portion of land will be subdivided.