Related Clues:

• Symbol for viscosity
• Metal core?
• Sigma-Upsilon connection
• In-flight info
• In-flight announcement
• Upsilon follower
• When a plane is due in: Abbr.
• Kind of lepton
• H, in Greece
• Homeric H
• Chi lead-in
• Last in a series
• Upsilon preceder
• Letter before Beta in a society's name
• H look-alike