"coffee ring" meaning in English

{
  "forms": [
    {
      "form": "coffee rings",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "coffee ring (plural coffee rings)",
      "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": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "coordinate_terms": [
        {
          "word": "water ring"
        }
      ],
      "derived": [
        {
          "word": "coffee ring effect"
        }
      ],
      "glosses": [
        "A brown ring-shaped stain left on a surface after a cup of coffee has been placed on it."
      ],
      "id": "en-coffee_ring-en-noun-vJkXz4wi",
      "links": [
        [
          "ring",
          "ring"
        ]
      ]
    }
  ],
  "word": "coffee ring"
}

{
  "derived": [
    {
      "word": "coffee ring effect"
    }
  ],
  "forms": [
    {
      "form": "coffee rings",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "coffee ring (plural coffee rings)",
      "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",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "coordinate_terms": [
        {
          "word": "water ring"
        }
      ],
      "glosses": [
        "A brown ring-shaped stain left on a surface after a cup of coffee has been placed on it."
      ],
      "links": [
        [
          "ring",
          "ring"
        ]
      ]
    }
  ],
  "word": "coffee ring"
}