[al-i-deyd] 
| 1. | (in plane-tabling) a straightedge having a telescopic sight or other means of sighting parallel to the straightedge. |
| 2. | the entire upper part of a theodolite or transit, including the telescope, its supports, the level vials, the circle-reading device, and the spindle. |
[al-i-dad] .
| al·i·dade (āl'ĭ-dād') n.
[French, from Medieval Latin alidada, sighting rod, from Arabic al-'iḍāda, the revolving radius of a circle : al-, the + 'iḍāda, revolving radius (alternate form of 'aḍud, humerus, from 'aḍada, to lop, cut (trees); see ʕ  d in Semitic roots).] |