What is the meaning of BPSK(n)
While I do not have proof, it seems pretty clear, given the "Characteristics of Compass signals reported as of May 2008 compared to GPS-L1CA" table at the Wikipedia page that you offered as an example, that the "(n)" notation refers to the chip rate.  You will notice that there is one BPSK(1) signal that has a chip rate of 1.023 Mchips/s.  There are four BPSK(2) signals listed, and all of them have a chip rate of 2.046 Mchips/s, which is twice 1.023 Mchips/s.  There are also three BPSK(10) signals that have a chip rate of 10.23 Mchips/s which is, of course, 10 times 1.023 Mchips/s.

It appears that the "(n)" notation means that the signal has a chip rate of $n*f_o$, and in the case of the Compass signals $f_o$ is 1.023 Mchips/s.