English
hollow block
See hollow + block, due to the hollow centers or cores that may be built into the production of these blocks to reduce weight.
Proto-Indo-European *ḱel- ‘to cover, hide’
…
Proto-Germanic *hulwiją ‘depression, hollow’
Proto-West Germanic *holh
Old English holh ‘a hollow’
Middle English holow
English hollow
Proto-Indo-European *bʰelǵ- ‘thick plank’
…
Old Dutch *blok ‘log’
Middle Dutch blok ‘treetrunk’
Old French bloc ‘log’
Middle English blok ‘log’
English block
Today it means
noun A lightweight building block made from cinders and concrete.
Language periods are conventional ranges, not dates for this word.
Etymograph / hollow block