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Webster 1913 Edition

Alidade

Al′i-dade

,
Noun.
[LL.
alidada
,
alhidada
, fr. Ar.
al-’idāda
a sort of rule: cf. F.
alidade
.]
The portion of a graduated instrument, as a quadrant or astrolabe, carrying the sights or telescope, and showing the degrees cut off on the arc of the instrument
Whewell.

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