An isometry is a transformation in geometry that preserves distances between points. This means that when a shape undergoes an isometric transformation, its size and shape remain unchanged, even though its position may vary. Common types of isometries include translations, rotations, and reflections. In practical terms, if you take a triangle and slide it across a plane without changing its angles or side lengths, you have performed a translation, which is an example of an isometry. Isometries are important in various fields, including mathematics, physics, and computer graphics, as they help maintain the integrity of shapes during transformations.