Correct spelling, explanation: souvenir is a noun of Latin origin as it derives from subvenire, which could be translated as to occur to the mind. Later, the word appeared in French, in which it already had the form of souvenir, but it meant to remember. Finally, in the 18th century, souvenir entered English, too.

Definition of souvenir:
1. noun – something that you keep in order to remember your holiday or some special event,
Every time I’m on holiday, I keep looking for a special souvenir, which will help me to remember this particular place.

Phrases with souvenir:
A few common phrases with souvenir include: souvenir shop, souvenir hunter, and souvenir industry.
If you want to find something really special, go to the souvenir shop on the corner of this street.
John is a true souvenir hunter so his house is full of beautiful things.
In the countries such as Egypt, the souvenir industry is one of the most flourishing businesses.

Incorrect spelling, explanation: a common spelling mistake made in the word souvenir is to write it with an extra -e letter in the last syllable, which results in souvenier – a form which is wrong. The mistake is probably the consequence of the pronunciation, which indeed might suggest that there is an extra -e letter. Nevertheless, the only correct spelling is souvenir.