drop (n.)
Middle English drope, from Old English dropa "a small, spherical mass of liquid," from Proto-Germanic *drupon (source also of Old Saxon dropo, Old Norse dropi, Dutch drop, Old High German tropfo, German Tropfen (n.)); see drop (v.).
Sense of "minute quantity of anything, least possible amount" is from c. 1200. Meaning "an act of dropping" is from 1630s; of immaterial things (prices, temperatures, etc.) from mid-19c. Meaning "lozenge, hard candy" is 1723, from resemblance in shape. Meaning "secret place where things can be left illicitly and picked up later" is from 1931. Theatrical meaning "painted curtain dropped between scenes to conceal the stage from the audience" is by 1779.
نوعی قوس نیشتری که مرکز کمان هر لنگهاش بر روی خط پاکار و در درون دهانهی قوس واقع است
”در قوس نیشتری کند، وتر هر کمان کوچکتر از دهانهی قوس است. | قوس نیشتری کند در کلیسا و کلیسیاهای گوتیک اسپانیا، مانند کلیسیای کوئنکا، به کار رفته است. “