black drop
/ˌblak ˈdrɒp/noun
1 Medicine. In singular or ( rare ) plural A dark-coloured liquid medicine composed of opium in vinegar or verjuice with various spices. Now historical.
2 Astronomy. A dark elongation of a planet's disc observed at the start and finish of solar transits of Venus and Mercury when the disc of the planet is just inside and touching the edge of the sun's disc, so that the planet briefly has a pear-shaped appearance elongated towards the sun's edge.
Origin
Early 19th century; earliest use found in The Caledonian Mercury. From black + drop.
- tweezers
- twelfth
- Twelfth Day
- twelfthly
- twelfth man
- Twelfth Night
- twelve
- twelve-bar
- twelve-bore
- twelvefold
- twelve-gauge
- twelve-incher
- twelve-inch single
- twelvemo
- twelvemonth
- twelve-note
- twelve-step
- twelve-stepper
- Twelve Tables
- twelve-tone
- Twelve Tribes of Israel
- twentieth
- Twentieth Century Fox
- twenty
- Twenty20