Sub-tending is a mathematical term that describes the relationship between two lines or angles. When one line or angle is positioned in such a way that it is connected to the ends of another line or angle, it is said to be sub-tending. There are several other synonyms that can be used to describe this relationship, including intersecting, overlapping, intersecting, crossing, and touching. Each of these terms describes a slightly different aspect of the relationship between two lines or angles, but all of them indicate that the two lines or angles are in close proximity and interacting in some way. Regardless of the specific word used, sub-tending is an important concept in geometry and trigonometry.