Upwards, Not Horizontal
This page is the CodyCross answer for the clue below from Physics, Group 1897, Puzzle 1 (Richard Feynman).
Question is: Upwards, Not Horizontal
and the answer is: VERTICAL
Word Meaning:
VERTICAL — Standing, pointing, or moving straight up or down; parallel to the local direction of gravity; along the direction of a plumb line; perpendicular to something horizontal.
Definitions from Wiktionary.