An Etymological Dictionary of Astronomy and Astrophysics

1. To → control or direct the → motion or course of.
   

2. Something that directs the motion or points the way. → autoguider, → guide star, → guider, → lightguide, → waveguide.

Etymology (EN): M.E. giden (v.), from O.Fr. guider “to guide, lead,” from Frankish *witan “show the way” (cf. Ger. weisen “to show, point out,” wissen “to know;” O.E. witan “to see”). Cognate with Pers. bin- “to see” (present stem of didan “to see”); Mid.Pers. wyn-;
O.Pers. vain- “to see;” Av. vaēn- “to see;”
Skt. veda “I know;” Gk. oida “I know,” idein “to see;” L. videre “to see;” PIE base *weid- “to know, to see.”

Etymology (PE): Râh bordan “to guide, conduct,” from râh “path, → way,” + bordan “to carry, lead,” → vector.