Since this is a 40’ container and sitting across both 9 and 11 bays, this bay is given the number 10. The container is shown as sitting on 9 but the corresponding slot on 11 is marked with an X which means that this slot is NOT available for placing another container because there is a 40’ container already there. Definition of SLOT in the Definitions.net dictionary. Meaning of SLOT. What does SLOT mean? Information and translations of SLOT in the most comprehensive dictionary definitions resource on the web.