(differential geometry) Given a point P on a surface M, the tangent plane of M at point P, denoted by T_P(M), is the plane passing through P which contains the tangent lines of all the curves on M ...

(chemistry) Describing any of the three unsaturated dicarboxylic acids obtained by the distillation of citric acid.

Of or relating to Mount Pentelicus (Penteliko Mountain), near Athens, famous for its fine white marble quarries.

Any therapy based on the circadian rhythm or other cyclical schedule.