Orientation describes the compass direction
Solar modeling often uses azimuth to describe direction. In the common convention used by PVWatts, 180 degrees is south, 90 degrees east and 270 degrees west.
South is not the only workable direction
A south-facing array often produces strong annual energy in the Northern Hemisphere, but east- and west-facing roofs can still be useful. The best economic orientation can depend on roof availability and time-of-use electricity pricing, not only total annual kWh.
Tilt changes seasonal production
Roof pitch affects the angle at which sunlight reaches the modules. The optimal fixed tilt varies by location and design goal, but residential systems usually follow the existing roof unless a flat-roof racking design sets a different angle.
Shade can matter more than a modest orientation difference
Trees, nearby buildings, dormers and other obstructions can reduce output during specific hours. A less-perfect compass direction with little shade may outperform a theoretically ideal roof section that is frequently shaded.
Model your actual roof
Use location-specific production modeling with the correct tilt and azimuth rather than applying one national production factor. Address-level roof data can improve the estimate further where coverage is available.