Final answer:
Imbibition is the term for when an alginate impression absorbs water, which can lead to dimensional changes and affect dental restoration accuracy.
Step-by-step explanation:
The term used when an alginate impression takes up water either from soaking or wrapping in a wet towel is called imbibition. This is a crucial concept in dental materials where proper handling of impressions is important to maintain the accuracy of the cast. If the impression absorbs too much water, it can lead to dimensional changes, potentially compromising the fit and function of dental restorations or appliances made from that impression.