1.2.42 तत्पुरुषः समानाधिकरणः कर्मधारयः

The तत्पुरुष of two entities that are the influence of the same object (another entity) are termed as कर्मधारय. For example, कृष्णा चतुर्दशी - कृष्णचतुर्दशी is कर्मधारय because कृष्णा and चतुर्दशी refer to the same object.