At least some content in this article is derived from information featured in Fantastic Beasts and Where to Find Them (film). As such, spoilers will be present within the article.
Newt Scamander shattered the front window of the Voclain & Co. jewellery store in New York using this spell to try and recapture his escaped niffler when he saw it loose inside the store stealing things.
The word finestra means "window" in Italian, Catalan and Sicilian. Given Rowling's use of puns in the construction of other incantations (e.g. Orchideous and Aguamenti), it is also possible that finestra is a sort of double entendre - a humorous blend of fine or finis, the Italian and Latin words for "end", and finestra for window. Taken together, this could allude to the spell's ironic capacity to destroy windows in the creation of an opening or "window".
Behind the scenes
- Bellatrix Lestrange is shown nonverbally casting this or a similar spell in the film adaptation of Harry Potter and the Half-Blood Prince, to shatter the windows of the Great Hall in a fit of joy following Albus Dumbledore's death.