Arabic
An alidade or turning board is a device that allows one to sight a distant object and use the line of sight. The word with that meaning was used by, e.g., the Persian mathematician and astronomer Abu al-Wafa' Buzjani (died 998) and Andalusian-Arab polymath Abu al-Salt (died 1134). With modern technology, the name is applied to complete instruments such as the plane table alidade.