baguette (n.)
1731, a type of architectural ornament, from French baguette "a wand, rod, stick" (16c.),
from Italian bacchetta, literally "a small rod," diminutive of bacchio "rod," from Latin baculum "a stick" (see bacillus).
The meaning "a diamond cut long" is from 1926; that of "a long, thin loaf of French bread" is from 1958.