diminutive

adjective
1
very small
کوچک, ریز, خرد
noun
1
a word or an ending of a word that shows that somebody/something is small, for example piglet(= a young pig), kitchenette(= a small kitchen)
کوچک‌نما, مصغر
2
a short informal form of a word, especially a name
صورت خلاصه شده, فرم کوتاه
‘Nick’ is a common diminutive of ‘Nicholas’.