Nexus Framework is designed for scaling Scrum by defining a workflow for three to nine Scrum Teams working on a single product development initiative. It helps to integrate the work of different teams into a single value stream, with the Nexus Integration Team (NIT) overseeing the process, solving conflicts, and eliminating obstacles. The NIT helps to ensure the generated increments are of a high quality and minimize dependencies.

Scrum of Scrums (SoS) is one of the straightforward techniques to scale Scrum. Teams coordinate their work through the SoS meeting, which consists of representatives from each Scrum Team. These representatives discuss their team’s progress, dependencies, and impediments. SoS acts like a Scrum Team where the product could be the result of synchronized projects of constituent teams.

The Scaled Agile Framework, or SAFe, provides a knowledge-based, organization-wide approach to scaling Scrum. The goal is to incorporate lean and agile principles throughout the technology enterprise. It focuses on alignment, transparency and program execution. This framework supports practitioners and teams with many roles, artifacts, and events that help large organizations deliver more complex products.

Large Scale Scrum (LeSS) offers the simplicity of Scrum while allowing its application to large-scale multi-team operations. It keeps a single product owner and a single product backlog, emphasizing multiple overlapping-development teams’ close coordination. LeSS involves potentially difficult organizational transformation however the methodology’s simplicity and principles-based approach offer flexibility and a concentration on long-term outcomes.

Scrum at Scale (Sc@le) is a scalable framework that reflects the basic principles of Scrum. Developed by Jeff Sutherland, it allows networks of Scrum teams to address complex problems while delivering products of the highest possible value. It maintains the flexibility of Scrum when achieving effective scalability and can be applied to any type of industry or organization.

Scaling Mastery revolves around the proficiency in applying Scrum principles and practices in large, complex projects. Mastery in this context includes a deep understanding of Scrum and the skill to effectively manage the challenges that arise during scaling. The concept focuses on how to maintain the transparency and inspection ability Scrum promotes while ensuring that multiple teams are working toward a common product goal. The Scrum Master should facilitate cross-team impacts, dependencies, and risks, integrating collaborative work rather than merely coordinating.

Metascrum is a concept that deals with aligning all the stakeholders with the product vision. It involves a meeting of the Product Owner and the stakeholders to prioritize the Product Backlog. While Scrum Master doesn't typically partake in the meeting, he or she guarantees that the meeting takes place and that everyone understands the process. The importance of this concept in the scaling context rests in its potential to ensure that all teams and their respective Product Owners are in line with the overall vision of the product they are collectively developing.

Cross-Team Coordination is a critical concept in scaling Scrum as it involves the way multiple Scrum teams interact with each other. One common mode of cross-team coordination is 'Communities of Practice' where members from different Scrum teams that have a shared interest in specific areas (e.g., testing, UX design) regularly interact to share ideas and practices. The Scrum Masters are often facilitators of these events and work to encourage cross-team collaboration. This helps to promote a shared understanding and consistency across all the Scrum teams within an organization.

In the context of scaling Scrum, Servant Leadership means that the Scrum Master takes a 'servant-first' approach, focusing on the needs of the team members before considering their own. As the Scrum teams grow in number, the principles of servant leadership become increasingly important. Scrum Masters at scale must focus on promoting a shared understanding, fostering an environment of open communication, granting teams the autonomy they need to self-organize while providing support, and ensuring alignment with the wider organizational goals.

Scaled Daily Scrum refers to the habit of conducting brief status meetings across multiple Scrum teams working on the same product. This meeting is a scaled-up version of the daily Scrum and provides a platform for different Scrum teams to synchronize their work and plans, discuss challenges and dependencies. This is a crucial part of integrating and synchronizing multiple Scrum teams' efforts and a duty of the Scrum Master to facilitate as part of their role.