Technical Debt (TD) contextualizes the technical decisions on shortcuts and workarounds during software development, positively and negatively influencing software evolution. However, TD still seems to confound with any issue occurring during software development, impacting its proper understanding and management in software projects. Goal: To synthesize evidence regarding the conceptualization, characteristics, and management of TD in software projects. Method: To undertake a tertiary study to strengthen the knowledge of TD using the principles of Grounded Theory to support qualitative analysis. Results: Nineteen secondary studies provide evidence on TD and its management. They provided information regarding the TD’s understanding (definitions and characteristics) and management (actions and technologies). Some causes, such as project constraints, technical decisions, and team members, promote different types of TD in software projects. The secondary studies also supported identifying the impacts of TD regarding project management, team members, the organization’s business, and internal software quality. Besides helping identify TD challenges, such studies contributed to integrating a conjectured conceptual model of TD that can support future discussions and investigations regarding TD’s understanding and management. Conclusions: The set of evidence regarding TD’s understanding, actions, and technologies to manage TD can aid software practitioners in their software projects. However, it is observable an interpretation overload regarding its definition, inducing to classify any issue occurring during the software development as TD. Therefore, further discussions and investigations still represent essential steps towards consolidating a common perspective on TD and its management.