In coin collecting a key date refers to a date ( or date and mint Mark combination ) of a givin coin series or set that is harder to obtain than other dates in the series. The next level of difficulty to obtain are semi-key dates. Hope this helps and good luck if you decide to bid.
Yes this does help and thank you so much. People on here are really nice and trying to answer all my questions. It means a lot to me to have your help. Thank you.