Definition of ACCRETION

• accumulation; the addition of parts to form a whole [n -S]
• The process of growth or increase, typically by the gradual accumulation of additional layers or matter
• The coming together and cohesion of matter under the influence of gravitation to form larger bodies
• A thing formed or added by such growth or increase
• the act or product of accreting [n ACCRETIONS] : ACCRETIVE [adj]