Related Clues:

• Rainbow, for one
• Flight segment
• Not the shortest line between two points
• You may step on it
• Way up or down
• Flight part
• Compass course?
• Go up in the middle
• One of a flight
• Smiley face smile
• Case beginning
• Part of a sector
• One step in a case?
• Parenthesis, e.g.
• It doesn't go full circle