オルト

Etymology 1
From.

Noun

 * 1) ortho-
 * 2)  a benzene ring with two substituents in adjacent positions
 * 3)  an oxyacid with a relatively large proportion of water
 * 1)  an oxyacid with a relatively large proportion of water

Etymology 2
Shortening of, from.

Noun

 * , alternative, alternate