From Investopedia: Net Asset Value

The net asset value (NAV) represents the net value of an entity and is calculated as the total value of the entity’s assets minus the total value of its liabilities

For dissolution I found this from Wikipedia:

Each SPAC has its own liquidation window within which it must complete a merger or an acquisition. Otherwise it is forced to dissolve and return the assets in the trust to the public stockholders.

Which probably means you can redeem your shares at the NAV (usually around $10) if the SPAC doesn't complete a merger or acquisition within the liquidation window (~2 years?).

Please correct me if I'm wrong. I'm still learning myself.