ve·loc·i·ty (v-ls-t) Am.Her

NOUN:
pl. ve·loc·i·ties
Rapidity or speed of motion; swiftness.
Physics; A vector quantity whose magnitude is a body's speed and whose direction is the body's direction of motion.
The rate of speed of action or occurrence.
The rate at which money changes hands in an economy.
ETYMOLOGY:
Middle English velocite, from Old French, from Latin vlcits, from vlx, vlc -, fast; see weg- in Indo-European roots

Online Etymology:
velocity c.1550, from L. velocitatem (nom. velocitas) "swiftness, speed," from velox (gen. velocis) "swift," of uncertain origin, perhaps related to vehere "carry" (see vehicle), or from the same root as vegetable (see vigil).

Quote:
speed:
O.E. sped "success, prosperity, advancement," from P.Gmc. *spodiz (cf. O.S. spod "success," Du. spoed "haste, speed," O.H.G. spuot "success," O.S. spodian "to cause to succeed," M.Du. spoeden, O.H.G. spuoten "to haste"), from PIE *spo-ti- "speed," from *spe- "to thrive, prosper" (cf. Skt. sphayate "increases," L. sperare "to hope," O.C.S. spechu "endeavor," Lith. speju "to have leisure"). Meaning "quickness of motion or progress" emerged in late O.E. (usually adverbially, in dative plural, e.g. spedum feran), emerging fully in early M.E. Meaning "gear of a machine" is attested from 1866. Meaning "methamphetamine, or a related drug," first attested 1967, from its effect on users. Speeder "one who drives fast" is recorded from 1891. Speedometer is from 1904, a hybrid coined with Gk. -metron.
[The ancient Greeks & Romans knew what speed was, & yet no-one supposes they called it speed, whence it follows that speedo- & speedometer are barbarisms." [Fowler] [/size]

**My question is: What word did the Greek and Romans use for speed if one etymology says (from Latin vlcits, from vlx, vlc-, fast[/b]) and the next (Fowler) talks about a barbarism?