What is the meaning of mon ami?

Answer 1

Mon amie is 'my (female) friend', mon ami is 'my (male) friend'.

It is mon amie, not ma, because amie starts with a vowel and so it would be more difficult to say. However, if you put an adjective in between the two words, then ma is used. (e.g. ma petite amie 'my girlfriend')

Answer 2

'Mon ami' means my friend (male) in English. If you're talking about a female friend, you would say 'mon amie.'

Normally you'd say 'ma amie' because the object of the sentence (in this case the friend) is feminine, but because the first word ends with a vowel and the second word begins with a vowel, you have to say 'mon amie' instead. That's how it is simply because it would be difficult to pronounce if the first word ended with an a, but normally you'd have to use 'ma' in front of an object if it is feminine.