The term 'Square Quartet' is composed of four words: 'Angles', 'Sides', 'AREA' and 'DIAGONALS'. The first two words, 'Angles' and 'Sides', refer to the properties of a square. A square has four angles, each measuring 90 degrees, and four sides of equal length. The third word, 'AREA', refers to the AREA of a square, which is calculated by multiplying the length of one side by itself. Finally, the fourth word, 'DIAGONALS', refers to the two lines that connect opposite corners of a square, forming two equal angles of 45 degrees. Together, these four words form the Square Quartet, which describes the properties of a square.