<p><strong>Verb</strong></p><ul><li>to cast or thrust forcibly or suddenly into something, as a liquid, a penetrable substance, a place, etc.; immerse; submerge: to plunge a dagger into one's heart.</li><li>to bring suddenly or forcibly into some condition, situation, etc.: to plunge a country into war; to pull a switch and plunge a house into darkness.</li><li>to place (a potted plant) up to its rim in soil or in certain other materials, as sand or moss.</li><li>to transit (the telescope of a transit or theodolite).</li></ul><p><strong>Synonyms</strong></p><ul><li>dive, rush, hasten</li></ul><p><strong>Noun</strong></p><ul><li>act of plunging.</li><li>a leap or dive, as into water.</li><li>a headlong or impetuous rush or dash: a plunge into danger.</li><li>a sudden, violent pitching movement.</li><li>a place for plunging or diving, as a swimming pool.</li></ul>