1. The gradual accumulation of land by natural forces, esp. as alluvium is added to land situated on the bank of a river or on the seashore. Cf. ALLUVION; AVULSION(2); DELICTION; EROSION. [Cases: Navigable Waters 44; Waters and Water Courses 93. C.J.S. Navigable Waters § 94; Waters §§ 177–182, 184–185.]
2. Any increase in trust property other than increases ordinarily considered as income. [Cases: Trusts 272–274. C.J.S. Trover and Conversion §§ 510, 539–554.]
3. Civil law. The right of heirs or legatees to unite their shares of the estate with the portion of any coheirs or legatees who do not accept their portion, fail to comply with a condition, or die before the testator.
4. A beneficiary’s gain through the failure of a coheir or colegatee to take his or her share.
5. Scots law. The perfection of an imperfect or defective title by some act by the person who conveyed title to the current holder. — accretive, accretionary, adj.