What does this mean....?

[Djuna]

I was looking at jobs in Vermont and came across this;

This is a bargaining unit position.

Can anyone explain what this means, it isn't a term I have come across working in Australia and New Zealand and I am trying to understand the whole job application process for the US.

Thanks for your help.

[ICRN2008, BSN, RN]

From what I understand, this means that the nurses in that facility have formed a union and have a collective bargaining agreement with the employer.