The term arterial has several meanings depending on its context.
In a general sense, it refers to anything related to blood vessels that carry oxygen-rich blood away from the heart. These are called arteries and they form an extensive network throughout the body.
However, in other fields such as geology or hydrology, "arterial" may refer to water flowing through natural channels or artificial conduits, typically towards a river or ocean. In this context, it is often used to describe the direction of water movement within a system.
In addition, arterial can also be used in relation to road networks where an 'arterial' refers to a main thoroughfare that connects different parts of a city or town and provides access to residential areas.