First angle projection is a method of creating a 2D drawing of a 3D object. It is mainly used in Europe and Asia and has not been officially used in Australia for many years. In Australia, third angle projection is the preferred method of orthographic projection.
Note the symbol for first angle orthographic projection. This is important information for the person interpreting the drawing because if you examine the diagram below you will note that in first angle orthographic projection:
FAP-O - First Angle Projection - Opposite