What is a "lagged bath"? First question, and this is one I've searched for in vain.

In the context of setting up cooling baths, I've come across the term "lagged" bath.  I cannot extract what this means from any available context.  I assume it has something to do with time passing (i.e. a lag), but I'm not certain.  If I had to guess, I'd assume it means allowing the cooling agent to come to equilibrium temperature, but again, not certain.

Any direct technical experience that can explain this term would be greatly appreciated.
I'm not 100% certain on this, but my best guess on this would be referring to 'lagged' as in 'lagging', as in insulation material. So, a lagged bath is an insulated bath.