"Tester" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "fro",
        "3": "testard",
        "4": "",
        "5": "someone with a big head"
      },
      "expansion": "Old French testard (“someone with a big head”)",
      "name": "der"
    }
  ],
  "etymology_text": "From Old French testard (“someone with a big head”), a pejorative from teste (“head”).",
  "forms": [
    {
      "form": "Testers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "Testers"
      },
      "expansion": "Tester (plural Testers)",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "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 surnames",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "A surname from Old French."
      ],
      "id": "en-Tester-en-name-0tkWYPLU",
      "links": [
        [
          "surname",
          "surname"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈtɛstə(ɹ)/"
    }
  ],
  "word": "Tester"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "fro",
        "3": "testard",
        "4": "",
        "5": "someone with a big head"
      },
      "expansion": "Old French testard (“someone with a big head”)",
      "name": "der"
    }
  ],
  "etymology_text": "From Old French testard (“someone with a big head”), a pejorative from teste (“head”).",
  "forms": [
    {
      "form": "Testers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "Testers"
      },
      "expansion": "Tester (plural Testers)",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        "English 2-syllable words",
        "English entries with incorrect language header",
        "English lemmas",
        "English proper nouns",
        "English surnames",
        "English surnames from Old French",
        "English terms derived from Old French",
        "English terms with IPA pronunciation",
        "English uncountable nouns"
      ],
      "glosses": [
        "A surname from Old French."
      ],
      "links": [
        [
          "surname",
          "surname"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈtɛstə(ɹ)/"
    }
  ],
  "word": "Tester"
}