The NB designation under bonding typically refers to a non-binding agreement between two parties. In the field of finance and investments, an NB bond or convertible bond is a type of corporate debt security that can be converted into a predetermined amount of the issuer's common stock at the holder's option within a specified timeframe.

Please note that the context and industry may influence the specific meaning of NB under bonding, so it's essential to consider the broader context and verify the correct definition based on the specific situation.