FROM STRONG’S GREEK DICTIONARY (1890)

Strong’s Greek Dictionary (1890) — public domain, printed whole.

orthos ὀρθός — or-thos' — probably from the base of 3735; right (as rising), i.e. (perpendicularly) erect (figuratively, honest), or (horizontally) level or direct:--straight, upright.

see GREEK for 3735