What term describes shapes that have the same size and shape?

The term that describes shapes that have the same size and shape is "congruent." When two shapes are congruent, it means they can be perfectly overlaid on one another without any gaps or overlaps; every side length and every angle measure is identical. This concept is foundational in geometry as it allows us to determine when two shapes are truly the same in all geometric aspects.

The other terms have specific meanings that differ from congruence. Similar shapes have the same shape but may differ in size; they maintain the same proportions but are not identical in size. Parallel refers to lines or shapes that run alongside each other without meeting, regardless of their size or shape. Identical can imply that two objects are exactly alike in appearance, but in mathematical terms, congruence is the more precise term used to describe the correspondence in size and shape of geometric figures. Thus, congruence is the correct term to denote the situation where shapes are exactly the same in every aspect.