The musical term alto, meaning high in Italian (Latin: altus), refers to the second highest part of a contrapuntal musical texture and is also applied to its associated vocal range, especially in choral music. It is also the root word of contralto, the lowest standard female voice type.
circle noun [ C ] (SHAPE) âº geometry a continuous curved line which is always the same distance away from a fixed central point, or the area enclosed by such a line: Colored paper was cut into circles, squares, and triangles. A circle of chairs had been arranged in the center of the room.
An arc is a portion of the circumference of a circle. In the figure above, the arc is the blue part of the circle. Strictly speaking, an arc could be a portion of some other curved shape, such as an ellipse, but it almost always refers to a circle. To avoid all possible mistake, it is sometimes called a circular arc.