Level One (inside market)
Definition - What does Level One (inside market) mean?
Level One is a NASDAQ workstation service that allows the agent to see the inside market only
Testopedia explains Level One (inside market)
Level one will allow an agent to see the inside market made up of the highest / best bid and the lowest / best offer from all bids and offers entered in to the NASDAQ workstation by market makers and ECNs. The inside market on level one NASDAQ is also known as the national best bid and offer or NBBO