"Overnight refrigeration" means to place something in a refrigerator and leave it there for the entire night, typically to cool or chill it. Full definition
«In the past, some customers have expressed that Soylent could have a slightly undesirable texture after overnight refrigeration,» according to a note on Soylent's website. (canadianbusiness.com)
Babymisu is also perfect for last minute dessert idea because it doesn't require overnight refrigeration, though you could still do it if you want. (brunchnbites.com)
This soup will benefit from overnight refrigeration, which allows the flavors to meld. (vegetariantimes.com)