In organisational communication, the 'grapevine' refers to:

The grapevine is the informal communication system that exists in all organisations, arising spontaneously from social relationships among employees rather than from official management structures. It spreads information — both accurate and inaccurate — faster than formal channels, often filling information vacuums when official communication is absent or unclear. Key characteristics: (1) it is rapid and crosses hierarchical boundaries; (2) it carries both factual information and rumours; (3) it is driven by employees' need for information, social interaction, and sense-making; and (4) management cannot fully control it but can influence it through timely, transparent official communication. Keith Davis identified four types of grapevine chains: Single strand, Gossip, Probability, and Cluster (the most common — a few well-connected individuals spread information to many). While often seen negatively, the grapevine also serves a social bonding function and provides management with informal feedback on employee morale.