a term used when a science fiction writer "waves his hands" at reality and hard science for the sake of the plot. Refers to all unrealistic or impossible technology, such as faster-than-light travel, teleportation, artificial gravity, etc.

Handwavium is extensively used in movies, more so than in literature, due to the need to mass market movies to a scientifically ignorant public and because filming realistic space travel is relatively expensive.

Got the covid-19 vaccine

A spell cast in D&D to show the passage of time. A joke the GM can make.