most of them are just the initials of the weapons.
there's no NMH, as far as i know.
this here is the link to the thread that has the unofficial guides for ToS:WS
guides
any way
SRM = short range missile
NM = napalm missile
LRM = long range missile
these are all unguided missiles.
GMH = guided missile, heat
GME = guided missile, energy
these are obviously guided missiles. most of these have numbers after them, and that's the number of missiles each rack fires at a single shot.
SL = small laser
ML = medium laser
PL = pulse laser
LL = large laser
PG= plasma gun
CLG = cold light gun
TB = tesla bolt
FT = flame thrower
BRG = black ray gun
NB = neutron blaster
EMP = E.M. pulser
MG = machine gun
AC = autocannon
GC = gauss cannon
LMG = light meson gun
HMG = heavy meson gun
PX = Power Axe
CS = Chain Saw
VC = Vibra Claw
everything else you wanna know about them, it's in the guides. Also if you check with F1 in the factory module.