m2 = m**2 = m2 = sq_meter = sq_m
m3 = m**3 = m3 = cu_meter = cu_m
cm2 = (cm)**2 = cm2 = sq_centimeter = sq_cm
cm3 = (cm)**3 = cm3 = cu_centimeter = cu_cm
ft2 = ft**2 = ft2 = sq_ft
ft3 = ft**3 = ft3 = cu_ft = cf
yr = year = yr = y
hr = hour = hr = h
d = day
USD = usd
ea = _ = each