‘Deus ex machina’ is commonly known as a plot device in creative writing where an apparently impossible situation is suddenly resolved with an unexpected and often far-fetched solution. It’s usage tends to be looked down upon by most writers.
The etymology of this phrase is an interesting one. ‘Deus ex machina’ is a New Latin phrase, and translates to English as ‘a god from a device,’ but is actually borrowed from the Greek language’s ‘god from a machine.’ This originates from Greek theatre, where Greek Gods were suspended over the stage during performances. They were usually written into plays to resolve the plot; hence why we use the term for such a literary device now.
Roman lyric poet Horace was famously known to advise other poets to never use this device in his famous discourse on poetics, Ars Poetica (circa 18 BC.)
Some writers will argue that using ‘deus ex machina’ at all is entirely improper. Writers consider it lazy, cliché or dated; but some writers use it on purpose, either to fit within a certain genre or style (i.e. superhero stories) or as parody.
‘Deus ex machina’ rarely makes it’s way into everyday speech or writing, but is occasionally used. Examples of use in a sentence include:
‘It’s almost if they expect ‘deus ex machina’ to save them from their self-inflicted mess.’
‘Bob used deus ex machina so his characters could escape their sticky situation.’