accretion
🇺🇸
/əˈkriːʃn/
🇬🇧
/əˈkriːʃn/
Something that gets bigger or thicker by having more added to it over time.
The accretion of dust on the old books made them look even older.
The act of growing by adding new parts or layers.
The slow accretion of layers formed a pearl inside the oyster.