Electricians make so many assumptions... is 'line' another way of saying 'neutral'?

Line typically means the hot side. Load is the side that is connected to the light or appliance. GFCI outlets are so marked. Neutral lines are on the down side. Current is not carried on a neutral unless something is connected and in use. If a light is plugged into an outlet but not turned on, power is only on the black supply. When the light is on, the neutral or white, has power.