alidade
/ˈalɪdeɪd
/noun
A sighting device or pointer for determining directions or measuring angles, used in surveying and (formerly) astronomy.A pointer, called an alidade, was pivoted at the centre of the disk....
- A wide variety of alidades and plane tables are available, both in manual and electronic versions.
- In the circle an index on the alidades gives the angle that they form with the vertical diameter.
Origin
Late Middle English: directly or (in modern use) via French and Spanish from Arabic al-‘iḍāda 'the revolving radius', probably based on aḍud 'upper arm'.
- the seven deadly sins
- the seven seas
- the seven-year itch
- the Seychelles
- the Shades
- the shape of things to come
- the sharp end
- the Shetlands
- the Shires
- the shirt off (or on) one's back
- the short end of the stick
- the sick man of ——
- Thesiger, Wilfred
- the silent majority
- the silent treatment
- the silly season
- the silver screen
- thesis
- the Six
- the sky is the limit
- the sleep of the just
- the slightest ——
- the small of the back
- the small screen
- the Smoke