Meaning of mutable sign

mu'table sign'

Pronunciation: [key]
  1. any of the four astrological signs, Gemini, Virgo, Sagittarius, or Pisces, that are grouped together because of their placement at the end of the seasons and characterized by the attribute of adaptability to circumstances. Cf.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.