The solar circle is the orbital path of the Sun around the galactic center. Sometimes the term is used to mean an exact circle that approximates the Sun's orbit, and other times it is used to mean the Sun's orbit, which has a small eccentricity and differs little from a circle. This distinction may be significant for some uses of the concept, but for other uses, it may be insignificant due to other contributors to ambiguity. For example, determination of the Sun's orbit is non-trivial and is subject to correction as methods improve, so useful precision is limited.
The radius of this circle, i.e., the distance to the galactic center is termed the solar galactocentric distance which is currently estimated to be in the range of 7.6 to 8.7 kpc.