1. An arc of coloured light in the sky caused by refraction of the sun's rays by rain
   "After the storm, a beautiful rainbow appeared in the sky"
    
2. An illusory hope
   "chasing rainbows"
    
3. An assortment, a varied collection
   "a rainbow of possibilities"

Derived forms: rainbows

Type of: arc, bow, hope, promise

Part of: sky

Encyclopedia: Rainbow, Rainbow