Jammming Project: setState()

https://www.codecademy.com/paths/full-stack-engineer-career-path/tracks/fscp-react-part-ii/modules/fecp-challenge

export default class SearchBar extends React.Component {
    constructor(props) {
        super(props);
        ...
    }
    render() {
        return (
        ...
        )
    }
    ...
    handleTermChange(event) {
        this.setState({term: event.target.value})
    }

The term property was never defined in the constructor. So you can just create the property with setState()? Can’t find any answers to this with Google.