A rake is an angle of slope measured from horizontal, or in some contexts from a vertical line 90° perpendicular to horizontal.
A 60° rake would mean that the line is pointing 60° up from horizontal, either forwards or backwards relative to the object.
Though the term may be used in a general manner, it is commonly applied in several specific contexts.
The rake of a ship's prow is the angle at which the prow rises from the water (the rake below water being called the bow rake). A motorcycle or bicycle fork rake is the angle at which the forks are angled down towards the ground.
In a theatre or opera house the stage can be raked to slope up towards the back of the stage to allow better viewing for the audience.