block

Concise Oxford English Dictionary © 2008 Oxford University Press:
block/blɒk/

▶noun

• 1 a large solid piece of hard material with flat surfaces on each side.

  ■ a starting block.

  ■ Printing a piece of wood or metal engraved for printing on paper or fabric.

  ■ a head-shaped mould used for shaping hats or wigs.

• 2 Brit. a large single building subdivided into separate flats or offices: a block of flats.

  ■ a group of buildings bounded by four streets.

  ■ N. Amer. the length of one side of such a block: he lives a few blocks away.

• 3 a large quantity or allocation of things regarded as a unit.

• 4 an obstacle to progress.

  ■ a chock for stopping the motion of a wheel.

• 5 a flat area, especially a solid area of colour.

• 6 a pulley or system of pulleys mounted in a case.

• 7 (also cylinder block or engine block) a large metal moulding containing the cylinders of an internal-combustion engine.

• 8 (also blockhole) Cricket the spot on which a batsman rests the end of the bat while waiting to receive a ball.

▶verb

• 1 prevent movement or flow in.

• 2 impede or prevent (an action or movement).

  ■ (often block something out) exclude (something unpleasant) from one's mind.

  ■ (in sport) impede with one's body.

  ■ Cricket stop (a ball) with the bat defensively.

• 3 impress a design on (a book cover).

• 4 (block something out/in) mark out an outline or shade something in roughly.

  ■ (as noun blocking) the physical arrangement of actors on a stage or film set.

• 5 shape (a hat) using a wooden mould.

– phrases
knock someone's block off informal hit someone very hard.
on the (auction) block for sale at auction.
put one's head (or neck) on the block informal put one's standing or reputation at risk by proceeding with an action.

– derivatives
blocker noun,
blocky adjective .

– origin ME (denoting a log or tree stump): from OFr. bloc (n.), bloquer (v.), from MDu. blok, of unknown ultimate origin.