# UIObjectTraitDefinition ``` @protocol UIObjectTraitDefinition ``` ## Topics ### Type Properties [`@property (class, nonatomic, readonly, nullable) id defaultValue;`](/documentation/UIKit/UIObjectTraitDefinition/defaultValue) The default value for this trait in a trait collection when no value has been set. ## Relationships ### Inherits From [`UITraitDefinition-3572h`](/documentation/UIKit/UITraitDefinition-3572h) ### Conforming Types [`UITraitResolvesNaturalAlignmentWithBaseWritingDirection-c.class`](/documentation/UIKit/UITraitResolvesNaturalAlignmentWithBaseWritingDirection-c.class) [`UITraitPreferredContentSizeCategory-c.class`](/documentation/UIKit/UITraitPreferredContentSizeCategory-c.class) [`UITraitTypesettingLanguage-c.class`](/documentation/UIKit/UITraitTypesettingLanguage-c.class) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)