Boundary between a plot of land or a building and the road onto which the plot or building fronts
Frontage is the boundary between a plot of land or a building and the road onto which the plot or building fronts. Frontage may also refer to the full length of this boundary. This length is considered especially important for certain types of commercial and retail real estate, in applying zoning bylaws and property tax. In the case of contiguous buildings individual frontages are usually measured to the middle of any party wall. .
https://en.wikipedia.org/wiki/Frontage