"first port of call" meaning in English

{
  "forms": [
    {
      "form": "first ports of call",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "first ports of call"
      },
      "expansion": "first port of call (plural first ports of call)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Nautical",
          "orig": "en:Nautical",
          "parents": [
            "Transport",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "_dis": "79 21",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "82 18",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "91 9",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "examples": [
        {
          "text": "After leaving from Southampton, our first port of call will be Gibraltar.",
          "type": "example"
        }
      ],
      "glosses": [
        "The first port that a vessel calls in at after the start of a voyage"
      ],
      "id": "en-first_port_of_call-en-noun-ZfU1qbNR",
      "links": [
        [
          "nautical",
          "nautical"
        ]
      ],
      "raw_glosses": [
        "(nautical) The first port that a vessel calls in at after the start of a voyage"
      ],
      "topics": [
        "nautical",
        "transport"
      ]
    },
    {
      "categories": [],
      "examples": [
        {
          "text": "When you move to a new country, your first port of call is often the local police.",
          "type": "example"
        },
        {
          "text": "To find the meaning of a word, your first port of call should be a decent dictionary.",
          "type": "example"
        }
      ],
      "glosses": [
        "The first place to go to start a process."
      ],
      "id": "en-first_port_of_call-en-noun-HuI3SsBi",
      "raw_glosses": [
        "(idiomatic) The first place to go to start a process."
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "en-au-first port of call.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/f/f8/En-au-first_port_of_call.ogg/En-au-first_port_of_call.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/f/f8/En-au-first_port_of_call.ogg"
    }
  ],
  "word": "first port of call"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English nouns",
    "Pages with 1 entry",
    "Pages with entries"
  ],
  "forms": [
    {
      "form": "first ports of call",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "first ports of call"
      },
      "expansion": "first port of call (plural first ports of call)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English terms with usage examples",
        "en:Nautical"
      ],
      "examples": [
        {
          "text": "After leaving from Southampton, our first port of call will be Gibraltar.",
          "type": "example"
        }
      ],
      "glosses": [
        "The first port that a vessel calls in at after the start of a voyage"
      ],
      "links": [
        [
          "nautical",
          "nautical"
        ]
      ],
      "raw_glosses": [
        "(nautical) The first port that a vessel calls in at after the start of a voyage"
      ],
      "topics": [
        "nautical",
        "transport"
      ]
    },
    {
      "categories": [
        "English idioms",
        "English terms with usage examples"
      ],
      "examples": [
        {
          "text": "When you move to a new country, your first port of call is often the local police.",
          "type": "example"
        },
        {
          "text": "To find the meaning of a word, your first port of call should be a decent dictionary.",
          "type": "example"
        }
      ],
      "glosses": [
        "The first place to go to start a process."
      ],
      "raw_glosses": [
        "(idiomatic) The first place to go to start a process."
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "en-au-first port of call.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/f/f8/En-au-first_port_of_call.ogg/En-au-first_port_of_call.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/f/f8/En-au-first_port_of_call.ogg"
    }
  ],
  "word": "first port of call"
}