jam[beau 7jam4bb#8
n.,
pl. 3beaux# 73bbz#8 5ME < OFr jambe: see JAMB6 GREAVE
French "jambeau" is leg. the "x" makes it plural. "bijou, caillou, chou, genou, hibou, joujou, pou"
a list I learned about 65 years ago. They all take "x" to make plural.

And greaves were armor that covered the anterior of lower leg.