1610s, "to block or stop up with obstacles or impediments," a back-formation from obstruction or else from Latin obstructus, past participle 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 sense of "to hinder, impede, retard, delay" (justice, the law, etc.) is by 1640s. Related: Obstructed; obstructing.
U.S. state, the region is traditionally said to have been named by Italian explorer Giovanni da Verrazzano when he passed through in 1524, based on an imagined similarity between modern Block Island and the Greek Isle of Rhodes. More likely it is from Roodt Eylandt, the name Dutch explorer Adriaen Block gave to Block Island c. 1614, literally "red island," so called for the color of its cliffs. Under this theory, the name was altered by 17c. English settlers by folk-etymology influence of the Greek island name (see Rhodes) and then extended to the mainland part of the colony. By 1685 the island had been renamed for Block. The Rhode Island red domestic fowl was so called by 1896, for its plumage.
1560s, "to take part in a masquerade" (a sense now obsolete); 1580s as "to wear a mask," also "disguise (feelings, etc.) under an assumed outward show;" from mask (n.) and French masquer. Military sense of "conceal" (a battery, etc.) from the view of the enemy" is from 1706. Related: Masked; masking. Masking tape recorded from 1927; so called because it is used to block out certain surfaces before painting.
1550s, "to drive and catch (swans)," from up (adv.). Intransitive meaning "get up, rise to one's feet" (as in up and leave) is recorded from 1640s. Sense of "to move upward" is recorded from 1737. Meaning "increase" (as in up the price of oil) is attested from 1915. Compare Old English verb uppian "to rise up, swell." Related: Upped; upping. Upping block, used for mounting or dismounting horses, carriages, etc., is attested from 1796 (earlier was horsing-block, 1660s).