partial derivative
derivative of a function of several variables with respect to one variable, with the others held constant
en-GB/ˈpɑːʃl dɪˈɹɪvətɪv/
en-US/ˈpɑɹʃəl dɚˈɪvɪtɪv/
derivative of a function of several variables with respect to one variable, with the others held constant