diff --git a/headers/os/drivers/PCI.h b/headers/os/drivers/PCI.h
index 20ed1e784e..154019a73b 100644
--- a/headers/os/drivers/PCI.h
+++ b/headers/os/drivers/PCI.h
@@ -572,7 +572,7 @@ struct pci_module_info {
 #define PCI_cap_id_agp          0x02      /* AGP */
 #define PCI_cap_id_vpd          0x03      /* Vital product data */
 #define PCI_cap_id_slotid       0x04      /* Slot ID */
-#define PCI_cap_id_mbi          0x05      /* Message signalled interrupt ??? */
+#define PCI_cap_id_msi          0x05      /* Message signalled interrupt ??? */
 #define PCI_cap_id_chswp        0x06      /* Compact PCI HotSwap */
 #define PCI_cap_id_pcix         0x07
 #define PCI_cap_id_ldt          0x08