What do you guys mean by "no losses"?

[Hento]

Originally Posted by CyberGuy

I keep seeing a lot of threads about "no loss" this and "no loss" that. Does it mean that you guys go into battle without a single loss of unit throughout the game? I find this to be impossible.

Nonsense, I completed original on hard with knight and mage with zero losses.

Also completed Starcraft campaign with zero losses, Tiberium Wars etc. etc.