parallactic instrument
historical
noun
An instrument invented by Ptolemy, consisting of three hinged rods (one vertical, one aligned along the observer's line of sight, and the third fixing the angle between the first two), used for calculating the parallax of the moon.
Origin
Late 17th century; earliest use found in Philosophical Transactions of the Royal Society of London.
- inexplicably
- inexplicit
- inexpressible
- inexpressibly
- inexpressive
- inexpressively
- inexpressiveness
- inexpugnable
- inextensible
- in extenso
- inextinguishable
- in extremis
- inextricability
- inextricable
- inextricably
- INF
- inf.
- in face (or the face) of
- in facsimile
- infall
- infallibility
- infallible
- infallibly
- infamous
- infamously