# bolt /ˈboʊɫt/ (US) · /bˈəʊlt/ (UK) Source: https://englishreference.com/word/bolt Updated: 2026-08-15 ## Senses ### 1. metal fastener noun · CEFR B1 a metal pin with a head at one end and a screw thread at the other, used with a nut to hold things together. For teachers: a cylindrical metal fastener with an external screw thread, designed to pass through holes in assembled parts and be secured by a nut. - He tightened the bolt on the bicycle wheel to make sure it was safe. - The engineer specified high-tensile steel bolts to ensure the bridge segments remained secure under extreme thermal expansion. ### 2. door lock noun · CEFR B1 a metal bar that you slide across a door or window to lock it. For teachers: a sliding bar or mechanism used to secure a door or window in a closed position. - She slid the bolt into place before going to bed for the night. - The heavy iron bolt had rusted into the staple, making it nearly impossible to open the garden gate without a hammer. ### 3. lightning noun · CEFR B2 a sudden flash of lightning that looks like a white line in the sky. For teachers: a sudden, distinct discharge of lightning, often referred to as a 'bolt of lightning'. - A bolt of lightning hit the old oak tree during the storm. - A jagged bolt of lightning illuminated the valley for a split second, followed immediately by a deafening crack of thunder. ### 4. roll of fabric noun · CEFR C1 · Technical a large roll of cloth or fabric. For teachers: a standard commercial unit of length for finished fabric, typically wound around a central core. - The tailor bought a whole bolt of silk to make the wedding dresses. - The warehouse stored hundreds of bolts of denim, organized by weight and dye lot for the garment factory. ### 5. to run away verb · CEFR B2 to run away suddenly, often because you are frightened. For teachers: to move or run away suddenly and rapidly, typically in response to fear or a sudden impulse. - The horse bolted when it heard the loud car engine. - As soon as the back door was left slightly ajar, the frightened stray dog bolted into the woods. ### 6. to lock verb · CEFR B1 to lock a door or window by sliding a metal bar across it. For teachers: to secure a door or window by means of a sliding bolt or similar mechanism. - Don't forget to bolt the door when you leave the house. - The shopkeeper carefully bolted the shutters every evening to protect the storefront from potential vandalism. ### 7. to eat quickly verb · CEFR C1 · Informal to eat your food very fast, often swallowing it without chewing much. For teachers: to swallow food or drink hurriedly or without adequate mastication. - He bolted his breakfast because he was late for the bus. - The hikers were so hungry that they bolted their rations in silence before collapsing into their sleeping bags. ### 8. to fasten with metal verb · CEFR B2 to join two things together using metal bolts. For teachers: to fasten or attach components together using threaded bolts. - The seats are bolted to the floor of the stadium. - The heavy machinery must be bolted to a concrete foundation to prevent vibration during high-speed operation. ### 9. plants growing too fast verb · CEFR C2 · Technical when a plant grows flowers and seeds too quickly, making it taste bad. For teachers: to produce flowers and seeds prematurely, often rendering the edible parts of the plant bitter or tough. - The lettuce started to bolt because the weather became too hot. - Gardeners often struggle to prevent spinach from bolting during unseasonably warm spring spells, which ruins the leaf quality. ### 10. completely upright adverb · CEFR B2 used with 'upright' to mean sitting or standing very straight. For teachers: in a rigid or sudden manner; almost exclusively used in the collocation 'bolt upright'. - She sat bolt upright in bed when she heard a strange noise. - The news caused him to sit bolt upright, his previous lethargy replaced by a sudden, sharp focus. ## Examples - He tightened the bolt with a wrench to stop the table from shaking. - The mechanic realized that a single rusted bolt was preventing the entire engine block from being removed. - Structural integrity depends on the precise tension of every bolt within the framework, as even a minor failure can lead to catastrophic mechanical stress across the assembly. --- From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.