CPA, in a way

• Used for maintaining equilibrium during flight
• Waiter, frequently
• Either of the club-like rudimentary hind wings of dipterous insects
• Gymnast, often
• Tightrope walker
• Fly appendage

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Balancer \Bal"an*cer\, n. One who balances, or uses a balance. (Zo["o]l.) In Diptera, the rudimentary posterior wing.

Wiktionary Word definitions in Wiktionary
n. 1 one who, or that which, balances 2 any of the rear wings of certain insects used for stability in flight

WordNet Word definitions in WordNet
n. an acrobat who balances himself in difficult positions either of the club-like rudimentary hind wings of dipterous insects; used for maintaining equilibrium during flight [syn: halter , haltere ]