Oxford Dictionary of Law

abandonment n. 1. The act of giving up a legal right, particularly a right of ownership of property. Property that has been abandoned is res nullius(a thing belonging to no one), and a person taking possession of it therefore acquires a lawful title. An item is regarded as abandoned when it can be established that the original owner has discarded it and is indifferent as to what becomes of it: such an item cannot be the subject of a theft charge. However, property placed by its owner in a dustbin is not abandoned, having been placed there for the purpose of being  collected as refuse. In marine insurance, abandonment is the surrender of all rights to a ship or cargo in a case of *constructive total loss. The insured person must do this by giving the insurer within a reasonable time a notice of abandonment, by which he relinquishes all his rights to the ship or cargo to the insurer and can treat the loss as if it were an actual total loss. 2. In civil litigation, the relinquishing of the whole or part of the claim made in an action or of an appeal. Any claim is now considered to be abandoned once a *notice of discontinuance is served, according to rule 38 (1) of the *Civil Procedure Rules. 3. The offence of a parent or guardian leaving a child under the age of 16 to its fate. A child is not regarded as abandoned if the parent knows and approves steps someone else is taking to look after it. The court may allow a child to be adopted without the consent of its parents if they are guilty of abandonment.
abatement n. 1. (of debts) The proportionate reduction in the payment of debts that takes place if a person’s assets are insufficient to settle with his creditors in full. 2. (of legacies) The reduction or cancellation of legacies when the estate is insufficient to cover all the legacies provided for in the will or on intestacy after payment of the deceased’s debts. The Administration of Estates Act 1925 provides that general legacies, unless given to satisfy a debt or for other consideration, abate in proportion to the amounts of those legacies; specific and demonstrative legacies then abate if the estate is still insufficient to pay all debts, and a demonstrative legacy also abates if the specified fund is insufficient to cover it. For example, A’s estate may comprise a painting, £300 in his savings account, and £700 in other money; there are debts of £100 but his will leaves the painting to B, £500 from the savings account to C. £800 to D, and £200 to E. B will receive the painting, C’s demonstrative legacy abates to £300, and after the debts are paid from the remaining £700, D’s and E’s general legacies abate proportionately, to £480 and £120 respectively.