<unk>  is a system of music in which certain hierarchical pitch relationships are based on a key "center" or tonic.  The term<unk>  originated with Alexandre-Étienne Choron (1810) and was borrowed by François-Joseph Fétis in 1840 (Reti, 1958; Simms 1975, 119; Judd, 1998; Dahlhaus 1990).  Although Fétis used it as a general term for a system of musical organization and spoke of types de<unk> s rather than a single system, today the term is most often used to refer to Major-Minor<unk>  (also called diatonic<unk>  or functional<unk> , the system of musical organization of the common practice period and most popular music in much of the world today.
Tonality
Density
Fluency
Intensity 
Molecular mass
Clean margin
Rape
Flammability