| progression | 1. The act of moving forward; a proceeding in a course; motion onward. 2. Course; passage; lapse or process of time. "I hope, in a short progression, you will be wholly immerged in the delices and joys of religion." (Evelyn) 3. <mathematics> Regular or proportional advance in increase or decrease of numbers; continued proportion, arithmetical, geometrical, or harmonic. 4. A regular succession of tones or chords; the movement of the parts in harmony; the order of the modulations in a piece from key to key. Arithmetical progression, a progression in which the terms increase or decrease by equal differences, as the numbers by the difference 2. Geometrical progression, a progression in which the terms increase or decrease by equal ratios, as the numbers by a continual multiplication or division by 2. Harmonic progression, a progression in which the terms are the reciprocals of quantities in arithmetical progression, as 1/2, 1/4, 1/6, 1/8, 1/10. Origin: L. Progressio: cf. F. Progression. Source: Websters Dictionary (01 Mar 1998) |
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| disease progression | The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis. (12 Dec 1998) |
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| tumour progression | <oncology> Second stage of tumour development. See: tumour initiation. (18 Nov 1997) |