"-en-" meaning in Néerlandais

{
  "categories": [
    {
      "kind": "other",
      "name": "Interfixes en néerlandais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Néerlandais",
      "orig": "néerlandais",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Néerlandais",
  "lang_code": "nl",
  "pos": "interfix",
  "pos_title": "Interfixe",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Exemples en néerlandais",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "paard + kracht → paardenkracht",
          "translation": "cheval + force, puissance → cheval-vapeur"
        },
        {
          "text": "tulp + bol → tulpenbol",
          "translation": "tulipe + boule → bulbe (de tulipe)"
        }
      ],
      "glosses": [
        "Interfixe sans signification reliant les deux parties d’un mot composé."
      ],
      "id": "fr--en--nl-interfix-QXY8-wtN"
    }
  ],
  "sounds": [
    {
      "ipa": "\\ən\\"
    },
    {
      "ipa": "\\ə\\"
    }
  ],
  "synonyms": [
    {
      "word": "-e-"
    }
  ],
  "tags": [
    "morpheme"
  ],
  "word": "-en-"
}

{
  "categories": [
    "Interfixes en néerlandais",
    "néerlandais"
  ],
  "lang": "Néerlandais",
  "lang_code": "nl",
  "pos": "interfix",
  "pos_title": "Interfixe",
  "senses": [
    {
      "categories": [
        "Exemples en néerlandais"
      ],
      "examples": [
        {
          "text": "paard + kracht → paardenkracht",
          "translation": "cheval + force, puissance → cheval-vapeur"
        },
        {
          "text": "tulp + bol → tulpenbol",
          "translation": "tulipe + boule → bulbe (de tulipe)"
        }
      ],
      "glosses": [
        "Interfixe sans signification reliant les deux parties d’un mot composé."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\ən\\"
    },
    {
      "ipa": "\\ə\\"
    }
  ],
  "synonyms": [
    {
      "word": "-e-"
    }
  ],
  "tags": [
    "morpheme"
  ],
  "word": "-en-"
}