"compression set" meaning in English

{
  "forms": [
    {
      "form": "compression sets",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "compression set (plural compression sets)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
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          "kind": "other",
          "name": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
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          "source": "w"
        },
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          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
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          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Physics",
          "orig": "en:Physics",
          "parents": [
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The tendency of soft materials, such as elastomers, to undergo permanent deformation; the tendency of such materials to have a memory or to lose their ability to recover in a completely elastic manner."
      ],
      "id": "en-compression_set-en-noun-WL-XWwzB",
      "links": [
        [
          "elastomers",
          "elastomers"
        ],
        [
          "deformation",
          "deformation"
        ],
        [
          "memory",
          "memory"
        ],
        [
          "elastic",
          "elastic"
        ]
      ],
      "related": [
        {
          "word": "viscoelastic"
        }
      ]
    }
  ],
  "word": "compression set"
}

{
  "forms": [
    {
      "form": "compression sets",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "compression set (plural compression sets)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "viscoelastic"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "en:Physics"
      ],
      "glosses": [
        "The tendency of soft materials, such as elastomers, to undergo permanent deformation; the tendency of such materials to have a memory or to lose their ability to recover in a completely elastic manner."
      ],
      "links": [
        [
          "elastomers",
          "elastomers"
        ],
        [
          "deformation",
          "deformation"
        ],
        [
          "memory",
          "memory"
        ],
        [
          "elastic",
          "elastic"
        ]
      ]
    }
  ],
  "word": "compression set"
}