{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "type": "array",
    "description": "Custom metadata for terms/expressions.",
    "additionalItems": {
        "type": "array",
        "description": "Metadata about a single term/expression.",
        "minItems": 3,
        "items": [
            {
                "type": "string",
                "description": "Term or expression."
            },
            {
                "type": "string",
                "enum": ["freq"],
                "description": "Type of data. \"freq\" corresponds to frequency information."
            },
            {
                "type": ["string", "number"],
                "description": "Data for the term/expression."
            }
        ]
    }
}