The use of ultrasound in the field of rheumatology practice and research has significantly increased in recent decades. Sonographers should be familiar with ultrasound knobology and appropriate transducer manipulation techniques to increase image quality and prevent the occurrence of artifacts. This chapter focuses on definitions related to ultrasound transducer manipulation. The third chapter provides an extensive overview of the ultrasound definitions utilized by OMERACT (Outcome Measures in Rheumatology), whereas this particular chapter emphasizes the European Alliance of Associations for Rheumatology (EULAR) ultrasound pathologies that OMERACT does not address. Additionally, this chapter includes definitions of ultrasound-guided interventional landmarks and advanced ultrasound imaging techniques, such as superb microvascular imaging (SMI), contrast-enhanced ultrasound, and elastography.