It's not, actually. People are just using the wrong term. Finance uses "correction" to mean an at least 10% but not 20% index drawback, with the correction peri

It's not, actually. People are just using the wrong term. Finance uses "correction" to mean an at least 10% but not 20% index drawback, with the correction period lasting until a new high is reached. When an index declines by 20%, they call that a bear market. It's just colloquial usage not matching the industry jargon.