Vertical
Perpendicular
noun, な adjective, の adjective
Something is dangling in front of you, so you fix it so it's straight and not moving. It becomes perfectly vertical, perpendicular to the floor.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ロケットは垂直に発射した。
The rocket took off vertically.