Well, you may call a Gladius a long knife, but I don't think the Gauls of 56 BC, who were gutted with them by Ceasar's legion, would have called them knives.  If the Gladius is not a sword, why is a Gladiolus  a small sword?  And if it's a knife, what is a Pugio?  (I know, a dagger - which is another word for knife).

It will come as some surprise to most scholars of ancient metallurgy that the Romans were unable to make steel.

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.