Final answer:
In a triangle, an altitude is a line segment drawn from a vertex and forming a right angle with the opposite side or its extension, and the intersection point of such altitudes is known as the orthocenter.
Step-by-step explanation:
An altitude in a triangle is a line segment drawn from a vertex perpendicular to the opposite side or to the line that contains the opposite side, forming a right angle. When we construct an orthocenter by drawing altitudes from each of the three vertices of a triangle to the opposite sides, the point where these three altitudes intersect is called the orthocenter. Therefore, an altitude is a line connecting the angle to the side to form a right angle.