RRRReally small stuff......!!!!
Ununiform units of uranium
Unified theories
Undulations
Van Allen, James Alfred
vacuum
vacuole
vulgar fraction
Weight
Wavelength
Work
Water
Watts
Y-chromosome
Year...the length of time for a planet to fully revolve
Yukawa-Tsuno equation
Yellowcake (product of uranium extraction in physics)
zones of audibility
zymase
zirconium
Zeeman effect
How about some classical myths or characters
for a change of pace?
Achilles
Adonis
Andromeda
Ariadne
Centaur
Ceres
Chaos
Cupid
Dido
Diana
Daphne
Delphinium