Deterrent: Measures taken to discourage or dissuade unwanted actions or behaviors, especially related to malicious activities. By imposing severe consequences or risks, deterrents aim to make the cost of carrying out harmful actions, such as unauthorized access or data breaches, outweigh any potential benefits. Examples include security awareness training to deter internal staff from unsafe practices or legal penalties for external actors to discourage hacking activities.

Deviations from Baselines: Deviations from Baselines refer to any variances observed from the expected or established standards (baselines) within IT and cybersecurity practices. These deviations might signal a range of issues, from system performance degradation to a potential security incident. Constant monitoring for such deviations is essential for timely identification and remediation to ensure system stability and security.

DevOps: A methodology that combines software development (Dev) and operations (Ops) with the aim of reducing the system development life cycle while delivering high-quality software and improving operational performance. DevOps fosters continuous integration, continuous deployment, and continuous monitoring in software development and operations, enabling quicker responses to changes and problems.

DevSecOps: An extension of the DevOps methodology, this approach integrates security into the development and operation processes. It advocates for security considerations and controls to be included from the initial stages of software development rather than being an afterthought or standalone phase. It underscores a "security as code" culture with ongoing, flexible collaboration between release engineers and security teams.

DFDs (Data Flow Diagrams): Graphical representations of the flow of data through an information system. They map out the data inputs, processing steps, data storage, and output processes involved in handling data. DFDs are used for system analysis and design and can help in understanding the complexities of systems, ensuring that all components are well-integrated and that the system functions as intended. They are particularly useful in visualizing data exchange within and between systems, aiding in error detection, and enhancing communication among stakeholders.

Dial Back: A security mechanism often used in remote authentication systems where the system disconnects a user after initial identification and then reconnects by dialing a pre-configured number. This process ensures that the connection is being established with a trusted source, thus reducing the risk of unauthorized access. It can be used in both telecommunications and networking environments to enhance security during remote access.