This is the 6895th most frequent Russian word.
айтсен
"Айтсен" is not a standard Russian word. It may be a typo or belong to a regional dialect/slang.
The word 'айн' is a colloquial address used similarly to 'hey you' or calling someone's attention, coming from Tatar/Mongolian origins.
Айн ты слышал об этом событии?
Ain, have you heard about this event?
Here, 'айн' is used as an address term, often signaling acquaintance or informal tone.
Скажи, айн, ты поможешь мне с этим проектом?
Tell me, Ayn, will you help me with this project?
In this sentence, 'айн' emphasizes the focus on the addressed person, drawing their attention.