"action of blocking up a way or passage, act of impeding passage or movement; fact of being obstructed," 1530s, from Latin obstructionem (nominative obstructio) "an obstruction, barrier, a building up," noun of action from past-participle stem of obstruere "build up, block, block up, build against, stop, bar, hinder," from ob "in front of, in the way of" (see ob-) + struere "to pile, build" (from PIE *streu-, extended form of root *stere- "to spread"). Figurative use is by 1650s.
"to cut with a quick blow," mid-14c., of uncertain origin, not found in Old English, perhaps from Old North French choper (Old French coper "to cut, cut off," 12c., Modern French couper), from Vulgar Latin *cuppare "to behead," from a root meaning "head," but influenced in Old French by couper "to strike" (see coup). There are similar words in continental Germanic (Dutch, German kappen "to chop, cut").
Related: Chopped; chopping. Chopping-block "block of wood on which anything (especially food) is laid to be chopped" is from 1703.
late 14c., "hinder, impede the movement of," originally by fastening a block of wood to something, from clog (n.). Meaning "choke up with extraneous matter" is 1670s; intransitive sense "become choked up with extraneous matter" is from 1755. Related: Clogged; clogging.
"upright slab," usually inscribed, 1820, from Greek stēlē "standing block, slab," especially one bearing an inscription, such as a gravestone, from PIE *stal-na-, suffixed form of root *stel- "to put, stand, put in order," with derivatives referring to a standing object or place. Related: Stelar.