Possible Clues:

• Trigonometrical ratio
• Relationship involving one of two sides
• Wrong to block firm with European function
• Math class ratio
• In a comparison of sides, wrong for runner to go round
• Function is elevated in solid figure
• Ratio in trigonometry
• Secant's reciprocal in trigonometry
• Trigonometrical function whose abbreviation is a type of lettuce
• Function of church, hiding old wickedness?