The word may have one of the following meanings.
- Nestor is also a archaeological site and a municipality in the west-southwestern part of Messenia
- In the Star Trek universe, a Nestor is a legal advisor to the offender in Cardassian criminal trials. Unlike the defense lawyer, the Nestor is barred from directly addressing the tribunal.
- In the book I, Robot and the movie I, Robot, Nestor is the common nickname of NS-series robots.