What does floodgate mean?
A floodgate is a gate constructed to regulate the passage of water, most often at the mouth of a sluice, channel, or reservoir, where it can be raised or lowered to admit water or hold it back. Engineered versions have guarded canals, harbours, and farmland for centuries, notably in low-lying regions such as the Netherlands where controlling water is a matter of survival. Beyond its literal meaning, floodgate has become one of English's most durable metaphors: to 'open the floodgates' is to remove a barrier and unleash an overwhelming, often unstoppable flow of something — tears, refugees, complaints, spending, or lawsuits. This figurative sense is so entrenched that it almost always appears in the plural, and it carries an unmistakable note of warning, implying consequences that will be difficult to contain once released. Judges, journalists, and politicians alike reach for the image whenever a single decision threatens to trigger a cascade of others.
A gate used to control the flow of water, especially at the entrance to a sluice or channel.
"Maintenance crews inspected every floodgate along the levee before the rainy season."
Often plural in both literal and figurative contexts.
Figuratively, a barrier whose removal allows an overwhelming outpouring of people, emotions, money, or similar things.
"The settlement threatened to open the floodgates to thousands of similar claims."
Almost always expressed in the plural form 'floodgates' in this sense.
The plural is standard for the physical structures when referring to a set of gates, and is overwhelmingly preferred in the figurative sense, as in 'open the floodgates'.
"Once the verdict was announced, the floodgates of public anger burst open."
For decades, British judges have worried that a single ruling might 'open the floodgates' — making this humble piece of hydraulic engineering one of the most-cited metaphors in all of English law.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of floodgate
Floodgate is a straightforward English compound of 'flood' and 'gate', both ancient Germanic words: 'flood' traces back through Old English flōd to Proto-Germanic roots shared with Dutch vloed and German Flut, while 'gate' comes from Old Norse gat, meaning an opening or passage. The literal structure — a gate that governs a flood of water — has been in use since the Middle Ages, particularly in land drainage and canal engineering. Its figurative extension, in which removing one gate releases an uncontrollable torrent, developed naturally from the physical device and is now the dominant usage. The Germanic root behind 'flood' ultimately connects to the Indo-European base meaning 'to flow', which also produced Latin-derived words such as fluent, flux, and influx.
Related word forms
How floodgate is actually used
In its figurative sense, floodgate appears almost exclusively in the plural ('open the floodgates'), typically followed by 'of' naming what pours through — tears, complaints, investment, litigation. The figurative use carries a connotation of suddenness and loss of control, and is common in journalism, politics, and law.