A woman who is highly experienced and knowledgeable in a particular field, subject, or line of work; expert
A female doyen.
The senior or eldest female member of a group, especially one who is most or highly respected.
An influential advisor or mentor.
In Indian traditions,it means a knowlegable teacher who guides his shishya(disciple/lit. seeker of [of knowledge or truth])
A Hindu or Sikh spiritual teacher.
To act as a guru; to give wise advice