TI seems to call it both:
"The ’HC4049 and ’HC4050 are fabricated with high-speed silicon gate technology. They have a modified input protection structure that enables these parts to be used as logic level translators which convert high-level logic to a low-level logic while operating off the low-level logic supply. For example, 15-V input pulse levels can be down-converted to 0-V to 5-V logic levels. The modified input protection structure protects the input from negative electrostatic discharge. These parts also can be used as simple buffers or inverters without level translation."
4049 inverts, 4050 buffers. Both do level conversion.