[philovivero]

Very much not generally nor always.

Source: I am a professional high-volume database guy doing this stuff since the mid 1990's and still deeply embedded with it now.

There are projects that have chosen other nouns, and they have ridden the wave of publicity around this, but by my estimation* more than 90% of database-related projects still use master/slave.

*as in I haven't done any formal record-keeping, nor will I.