The "wage base limit" refers to the maximum amount of an employee's earnings that are subject to certain payroll taxes, such as those for Social Security. Once an employee's income exceeds this limit, additional earnings are not taxed for that specific program. This limit is adjusted annually to account for inflation and changes in average wages. For example, in 2023, the wage base limit for Social Security was set at $160,200. This means that only the first $160,200 of an employee's earnings would be taxed for Social Security contributions, while any income above this threshold would not be subject to the tax.