Final answer:
Leading refers to the space between lines of text, not between two letters. For letter spacing, the term kerning or tracking is used. Leading space in visual arts allows for the depiction of direction of movement.
Step-by-step explanation:
The term leading in typesetting refers to the vertical space between lines of text, not the space between two letters. The space between letters is actually known as kerning or letter-spacing. However, a concept similar to leading called tracking can affect the overall spacing across a group of letters in a line of text, but this is still different from leading.
The use of leading space in photography and visual arts is to create a direction of movement by allowing space in front of a moving subject. It guides the viewer's eyes in the direction the subject appears to be moving towards, making the composition dynamic. Similarly, in typography, managing space can influence readability and aesthetic of the text layout.