A mass, usually with flat surfaces
slab, chunk, piece, square, cake, cube, slice, segment, loaf, clod, bar, ingot, oblong, section, mill end, hunk*; see also brick, slab, stone.
The area between streets
square, city square, lots, neighborhood; see neighborhood.
The distance of the side of a block, sense 2
street, city block, intersection; see distance 3.
An obstruction
hindrance, bar, obstacle; see barrier.
In sports, an obstruction to a move or play
charge, tackle, check, body check, body block, running block, cross-body block, downfield block, pick (in basketball).
A massive object
chunk, mass, impediment, solid, cylinder block, slab, base; see also sense 1.
A pulley
sheave, wheel, hoist, rope-block, chain-block, lift.
A chunk used for chopping
chopping block, slab, breadboard, cheeseboard, table, butcher block, cutting board.
Place of execution
headsman's block, guillotine, scaffold, stake, tree, cross, gibbet; see also gallows.