"main memory" meaning in English

{
  "forms": [
    {
      "form": "main memories",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "main memory (countable and uncountable, plural main memories)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
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          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Esperanto translations",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Greek translations",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Computing",
          "orig": "en:Computing",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Volatile memory forming most of a computer’s primary storage, not including cache memory (central processing unit cache) and secondary storage (mass storage)."
      ],
      "id": "en-main_memory-en-noun-D~OTFTYu",
      "links": [
        [
          "computing",
          "computing#Noun"
        ],
        [
          "Volatile memory",
          "volatile memory"
        ],
        [
          "computer",
          "computer"
        ],
        [
          "primary storage",
          "primary storage"
        ],
        [
          "cache",
          "cache#English"
        ],
        [
          "central processing unit",
          "central processing unit"
        ],
        [
          "secondary storage",
          "secondary storage"
        ],
        [
          "mass storage",
          "mass storage"
        ]
      ],
      "raw_glosses": [
        "(computing) Volatile memory forming most of a computer’s primary storage, not including cache memory (central processing unit cache) and secondary storage (mass storage)."
      ],
      "tags": [
        "countable",
        "uncountable"
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ],
      "translations": [
        {
          "code": "eo",
          "lang": "Esperanto",
          "sense": "computing",
          "word": "ĉefmemoro"
        },
        {
          "code": "el",
          "lang": "Greek",
          "roman": "kýria mními",
          "sense": "computing",
          "tags": [
            "feminine"
          ],
          "word": "κύρια μνήμη"
        },
        {
          "code": "el",
          "lang": "Greek",
          "roman": "kentrikí mními",
          "sense": "computing",
          "tags": [
            "feminine"
          ],
          "word": "κεντρική μνήμη"
        }
      ],
      "wikipedia": [
        "Computer data storage"
      ]
    }
  ],
  "word": "main memory"
}

{
  "forms": [
    {
      "form": "main memories",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "main memory (countable and uncountable, plural main memories)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English uncountable nouns",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Esperanto translations",
        "Terms with Greek translations",
        "en:Computing"
      ],
      "glosses": [
        "Volatile memory forming most of a computer’s primary storage, not including cache memory (central processing unit cache) and secondary storage (mass storage)."
      ],
      "links": [
        [
          "computing",
          "computing#Noun"
        ],
        [
          "Volatile memory",
          "volatile memory"
        ],
        [
          "computer",
          "computer"
        ],
        [
          "primary storage",
          "primary storage"
        ],
        [
          "cache",
          "cache#English"
        ],
        [
          "central processing unit",
          "central processing unit"
        ],
        [
          "secondary storage",
          "secondary storage"
        ],
        [
          "mass storage",
          "mass storage"
        ]
      ],
      "raw_glosses": [
        "(computing) Volatile memory forming most of a computer’s primary storage, not including cache memory (central processing unit cache) and secondary storage (mass storage)."
      ],
      "tags": [
        "countable",
        "uncountable"
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ],
      "wikipedia": [
        "Computer data storage"
      ]
    }
  ],
  "translations": [
    {
      "code": "eo",
      "lang": "Esperanto",
      "sense": "computing",
      "word": "ĉefmemoro"
    },
    {
      "code": "el",
      "lang": "Greek",
      "roman": "kýria mními",
      "sense": "computing",
      "tags": [
        "feminine"
      ],
      "word": "κύρια μνήμη"
    },
    {
      "code": "el",
      "lang": "Greek",
      "roman": "kentrikí mními",
      "sense": "computing",
      "tags": [
        "feminine"
      ],
      "word": "κεντρική μνήμη"
    }
  ],
  "word": "main memory"
}