Epsilon Legato
Epsilon Legato was a star system in the Beta Quadrant.
In 2366, Epsilon Legato's position was labeled on a Starfleet Tactical analysis star chart, placing it within the Federation-Romulan border. (TNG: "The Defector" okudagram)
This star system was only mentioned in writing.
This star system's quadrant of origin was inferred based on the location of Sigma Nelvana's system as seen in the star charts appearing in "The Defector" and in the Star Trek: Picard episode "Maps and Legends".
In the Bayer designation, which was a system of stellar classification, the Greek letter indicated the brightness of a star in a constellation. In this case, Epsilon Legato would be the 5th brightest star in its constellation.