"happen along" meaning in English

{
  "forms": [
    {
      "form": "happens along",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "happening along",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "happened along",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "happened along",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "happen along (third-person singular simple present happens along, present participle happening along, simple past and past participle happened along)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English phrasal verbs formed with \"along\"",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1892, Julian Hawthorne, chapter 1, in The Golden Fleece:",
          "text": "\"Now, if a rattling good earthquake were to happen along, you might awake in the morning to find yourself on an island, or even under water.\"",
          "type": "quote"
        },
        {
          "ref": "1909, L. Frank Baum, chapter 11, in The Road to Oz:",
          "text": "\"[W]e can't 'spect a cyclone to happen along and take us to the Emerald City now.\"",
          "type": "quote"
        },
        {
          "ref": "1928 April 9, “Science: Heavenly Hubbub”, in Time:",
          "text": "Novae, or new stars, are always happening along.",
          "type": "quote"
        },
        {
          "ref": "2001, Linwood Barclay, Bad Move, →ISBN, page 148:",
          "text": "\"Well, you're the one who's always telling me not to leave my purse in the cart, and that's probably what that woman had done, and someone happened along and just took it.\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "To arrive by chance; to occur by happenstance."
      ],
      "id": "en-happen_along-en-verb-svkup0FK",
      "links": [
        [
          "arrive",
          "arrive"
        ],
        [
          "chance",
          "chance"
        ],
        [
          "occur",
          "occur"
        ],
        [
          "happenstance",
          "happenstance"
        ]
      ],
      "raw_glosses": [
        "(intransitive, idiomatic) To arrive by chance; to occur by happenstance."
      ],
      "tags": [
        "idiomatic",
        "intransitive"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "en-au-happen along.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/4/4c/En-au-happen_along.ogg/En-au-happen_along.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/4/4c/En-au-happen_along.ogg"
    }
  ],
  "word": "happen along"
}

{
  "forms": [
    {
      "form": "happens along",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "happening along",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "happened along",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "happened along",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "happen along (third-person singular simple present happens along, present participle happening along, simple past and past participle happened along)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English idioms",
        "English intransitive verbs",
        "English lemmas",
        "English multiword terms",
        "English phrasal verbs",
        "English phrasal verbs formed with \"along\"",
        "English terms with quotations",
        "English verbs",
        "Pages with 1 entry",
        "Pages with entries",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "1892, Julian Hawthorne, chapter 1, in The Golden Fleece:",
          "text": "\"Now, if a rattling good earthquake were to happen along, you might awake in the morning to find yourself on an island, or even under water.\"",
          "type": "quote"
        },
        {
          "ref": "1909, L. Frank Baum, chapter 11, in The Road to Oz:",
          "text": "\"[W]e can't 'spect a cyclone to happen along and take us to the Emerald City now.\"",
          "type": "quote"
        },
        {
          "ref": "1928 April 9, “Science: Heavenly Hubbub”, in Time:",
          "text": "Novae, or new stars, are always happening along.",
          "type": "quote"
        },
        {
          "ref": "2001, Linwood Barclay, Bad Move, →ISBN, page 148:",
          "text": "\"Well, you're the one who's always telling me not to leave my purse in the cart, and that's probably what that woman had done, and someone happened along and just took it.\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "To arrive by chance; to occur by happenstance."
      ],
      "links": [
        [
          "arrive",
          "arrive"
        ],
        [
          "chance",
          "chance"
        ],
        [
          "occur",
          "occur"
        ],
        [
          "happenstance",
          "happenstance"
        ]
      ],
      "raw_glosses": [
        "(intransitive, idiomatic) To arrive by chance; to occur by happenstance."
      ],
      "tags": [
        "idiomatic",
        "intransitive"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "en-au-happen along.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/4/4c/En-au-happen_along.ogg/En-au-happen_along.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/4/4c/En-au-happen_along.ogg"
    }
  ],
  "word": "happen along"
}