Define 'tax bracket.'

A tax bracket refers to a range of incomes that are taxed at a specific rate. In most tax systems, individuals or households fall into different categories based on their income levels, with each category (or bracket) being subjected to a different tax rate. This progressive tax structure means that as a person's income increases, not all of their income is taxed at the same rate; rather, it is segmented into brackets where each segment is taxed at increasing rates. Understanding tax brackets helps individuals plan their finances and understand their tax liabilities more clearly.