Masses-interactions modeling, also called physics Newtonian networks modeling, was pioneered in the late 70’s with the CORDIS-ANIMA formalism. It is a modular physics-based approach, used in sound design, musical instruments design and musical composition, and also in computer graphics animation, virtual reality, gesture interaction, and more generally for digital creativity. Within the research that progressively position physicsbased modeling as a core mean to improve creativity with the computer, the paper introduces the Physics Network Scripting Language. PNSL is aimed at accompanying the modeling processes of any user, including artists, with masses-interactions modeling. It serves in particular, but not only, sound and musical purposes. The paper describes the PNSL language: context, goals and general choices; labeling system tailored to support modeling complexity by managing freely large module sets; main features and syntax choices; and implementation and exemplary usage contexts.