- block
- "solid piece," c.1300, from O.Fr. bloc "log, block" (13c.), via M.Du. bloc "trunk of a tree" or O.H.G. bloh, both from PIE *bhlugo-, from *bhelg- "a thick plank, beam" (see balk). Slang sense of "head" is from 1630s. The meaning in city block is 1796, from the notion of a "compact mass" of buildings; slang meaning "fashionable promenade" is 1869. Extended sense of "obstruction" is first recorded 1640s. The verb "to obstruct" is from 1560s.