Related Clues:

• Life force, in Eastern philosophy
• Midwest city, slangily
• Pi follower
• See 6-Down
• Home of the Bears and the Bulls: Abbr.
• X
• See 51-Down
• See 48-Across
• See 31-Across
• Greek consonant
• Certain fraternity chapter
• Letter before sigma
• See 16-Down
• ___-square
• Density symbol, in mechanics