To attempt to explain or justify behavior or an attitude with logical reasons, even if these are not appropriate. She tried to rationalize her decision to quit her job by saying she needed more time for her family.
To make a process or system more efficient by reorganizing it. The company decided to rationalize its operations to cut costs and improve productivity.
To remove unnecessary elements from something to make it more efficient. The government plans to rationalize the public transport system to reduce congestion.
To eliminate radicals or imaginary numbers from the denominator or from an algebraic expression, usually by multiplying by a suitable quantity. In order to simplify the fraction, the teacher asked the students to rationalize the denominator.