pystysuuntaa
Pystysuunta is a Finnish term meaning vertical direction. It denotes the direction pointing upward relative to a chosen horizontal reference, and is used across fields to describe motion, forces, and orientation along the vertical axis. In mathematical contexts, pystysuunta refers to the vertical axis of a coordinate system. In a two-dimensional Cartesian system, this is typically the y-axis; in three-dimensional systems the vertical axis is context dependent and may be labeled z or another symbol depending on convention.
In geodesy, cartography, and navigation, pystysuunta is used to describe vertical components of vectors and to
The term is often contrasted with vaakasuunta, the horizontal direction, which runs left-right in the same reference
See also: horizontal direction, vertical axis, gravity, coordinate system, vector decomposition.