packing box
- noun
- Specialized
- You must replace the worn packing in the packing box to maintain an effective seal.
Examples
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The packing box was filled with foam.
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The engineer inspected the packing box for signs of leakage before starting the machine.
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Routine maintenance of the packing box extends the lifespan of the pump.
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Is the packing box ready for use?
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The technician inspected the packing box to ensure it was secure and functioning properly.
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To prevent any leaks, it is essential to fill the packing box tightly with the right material around the shaft.
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During the maintenance check, the engineer found that the packing box had worn out and needed replacement.
Synonyms
A small space around a moving shaft filled with packing material to make a seal and stop leaks
Surface Forms
Morphology
The phrase is compositionally built from 'packing' + 'box' so a learner who knows both words would likely infer a container related to packing material (e.g., a box with foam). However, the provided technical sense (a sealed chamber compressing packing around a shaft) is specialized and not directly predictable from the everyday meanings, so the expression is not fully transparent to a B1 learner.
Etymology
Packing box comes from a small box that holds the packing — material like rope or cloth — pressed around a moving rod to stop leaks. So it means a small chamber that creates a 'seal' around a shaft or piston to prevent leakage.