node

noun

• 1a point in a network or diagram at which lines or pathways intersect or branch: the intersections of two or more such arteries would clearly become major nodes of traffic and urban activity
• a piece of equipment, such as a computer or peripheral, attached to a network: the company’s internal worldwide area network now has some 22,000 nodes every node on the Internet
• Mathematics a point at which a curve intersects itself.
• Astronomy either of the two points at which a planet’s orbit intersects the plane of the ecliptic or the celestial equator.

• 2 Botany the part of a plant stem from which one or more leaves emerge, often forming a slight swelling: the stem is cut midway between nodes

• 3 Anatomy a lymph node or other structure consisting of a small mass of differentiated tissue: infection in these nodes may lead to backache

• 4 Physics & Mathematics a point at which the amplitude of vibration in a standing wave system is zero.
• a point at which a harmonic function has the value zero, especially a point of zero electron density in an orbital.
• a point of zero current or voltage.