I have seen people write or say this sometimes but I am not sure exactly what they mean ot how to use them.Can someone give some examples?

If you look for "per se" (the correct spelling) in these forums, you'll find a lot of information on that one.

"Per your request" just means "As you requested."

Per your request, I have reserved a room for you the nights of May 23 and 24."
Students: Are you brave enough to let our tutors analyse your pronunciation?
Also, does per itself mean: each or each of?

what about perhaps, performance, percent, perfect... Do they have something in common?
The words that you quoted above have nothing more in common than the first three letters, p-e-r. Emotion: smile This collection of three letters 'p-e-r' does not have a particular meaning to connect the various words that you wanted to know about, like perhaps, performance, and perfect.

However, the word 'percent' is really a combinatin of at least two parts, 'per' and 'cent'. Per means each, and cent refers to one-hundredth-part. (Also however remember that 'per' can have other meanings too, in other situations). So percent means per-hundredth-part. You might recall that each dollar is made of 100 cents. This can also be said such, that each dollar is made of 100 hundredth parts. 5 percent, therefore means, 5 of one hundredth parts, or, more simply 5 one hundredth parts. In words that are similarly made of two parts, and the first part is 'per', the first part is called 'prefix'. The prefix gives a particular meaning to the words that use them. Other words with prefix 'per' are, per-annum, per-capita, etc. Please remember however, like I wrote before, that all words starting with 'per' do not always use it as a prefix.

I hope it was helpful.

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