Right-angled shapes, also known as rectilinear shapes, are shapes that have 90-degree angles. The term 'right-angled shapes' is often used to refer to squares and rectangles, but can also include other shapes such as rhombuses and trapezoids. The crossword solution for this term is ELLS, which stands for 'equal-length sides'. This means that all four sides of the shape have the same length, making it a right-angled shape.