It means what it means. Consider a fluid (imagine e.g. liquid water) which fills a box of constant volume at a given temperature T. Now, if you close the box, keep its volume constant and decrease temperature, the pressure will decrease, and, if the formation of bubbles is somehow inhibited, may even become negative, i.e. the liquid pulls from inside on the box instead of pushing as usual.
The same can happen with a gas (which is also a fluid) as long as drop formation is kinetically inhibited due to the high surface tension of small droplets.
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