In pulse code modulation what is pulse word represent?
Think of a DAC as a thing that is emitting a train of pulses, each new one hard up against the last one, and each one exactly as wide as a sampling interval (sampling interval = $T_s = \frac{1}{f_s}$).
The code in PCM is the height of each pulse.
And if the name seems odd now, just remember that it made perfect sense in the 1925 to 1948 time period when the basis for this stuff was being laid down.