The term gesture has been used widely but inconsistently in describing music, largely in terms of analogies and metaphors of human physicality and rhetoric.
The term is useful in electroacoustic music studies, where it also receives wide, and precise, usage in the areas of Interactivity and Spectromorphology.
Much research in the field of Interactivity and the construction of new musical instruments and interfaces is concerned with the detection and translation of physical movement. The terms gesture mapping and gesture capture are apropos in this context.
Denis Smalley has written extensively on the concept of the pairing of Gesture and Texture as structuring principles in electroacoustic composition and analysis.
Gesture is concerned with action directed away from a previous goal or towards a new goal; it is concerned with the application of energy and its consequences; it is synonymous with intervention, growth and progress, and is married to causality. (Source - Denis Smalley (1986). Spectro-morphology and Structuring Processes, in Simon Emmerson, ed. The Language of Electroacoustic Music. Basingstoke: Macmillan.)