ACCRETION, the growth or increase of an organic body by the accession of new parts. See NUTRITION.

Accretion is of two kinds; the one consisting in an external apposition of new matter. This is what we otherwise call Juxtaposition; and thus, stones, shells, etc. are supposed to grow. See STONE and SHELL.

The other is by some solid matter received into proper vessels and gradually brought to adhere or grow to the sides thereof. This is what we call Intussusception; and thus, plants and animals are nourished. See PLANT and ANIMAL; see also NUTRITION.

Accretion, Accrement, in the Civil Law, a vague or vacant portion of ground, joined or united with grounds held or possessed by another. A legacy given to two persons jointly, tam re quam verbis, goes wholly to him that survives the testator, by right of accretion. Alluvion is another species of accretion. See ALLUVION.