Webster's Revised Unabridged Dictionary · 1913

Elongation

Elongation (?; 277) , noun

[Late Latin elongatio: compare French élongation.]

1.
The act of lengthening, or the state of being lengthened; protraction; extension.
Elongation of the fibers. — Arbuthnot
2.
That which lengthens out; continuation.
May not the mountains of Westmoreland and Cumberland be considered as elongations of these two chains? — Pinkerton
3.
Removal to a distance; withdrawal; a being at a distance; distance.
The distant points in the celestial expanse appear to the eye in so small a degree of elongation from one another, as bears no proportion to what is real. — Glanvill
4.
(Astronomy) The angular distance of a planet from the sun; as, the elongation of Venus or Mercury.