That is certainly like this bowl, pink with milky bits, but perhaps the use of the term there might be confined to carnival glass - or it may be an Americanism, m. (like "vaseline" for clear-milky uranium glass, but not for uranium custard glass)
To me opalescent glass is the stuff which is coloured with arsenic, and gives "fire" when light comes through it. It is milky opaque, with blues, yellows and reds showing, depending on the thickness of the glass - that's the fire.
It's the stuff typically used by Sabino, Jobling and Lalique - as well as others.
I don't think :spls: glass coloured with arsenic is used in carnival glass - it would be a bit silly, given the lustre-ing would cover it up!