What does UEFI boot mode mean?

Related questions

1. What are the advantages of UEFI?
2. Is EFI same as UEFI?
3. Is Ubuntu a UEFI or legacy?
4. What is better BIOS or UEFI?
5. Should I do MBR or GPT?
6. Is Windows 7 UEFI or legacy?
7. Is Legacy or UEFI better?
8. How do I change the boot mode from Uefi to legacy Toshiba?
9. How do I change from Uefi to legacy on Windows 10?
10. Which is faster MBR or GPT?

Tags

1. #operating
2. #unified
3. #computer
4. #system
5. #eventually
6. #interface
7. #first
8. #manufacturing
9. #expected
10. #extensible
11. #software
12. #specification
13. #installed
14. #program
15. #turned
16. #connects
17. #firmware
18. #replace