What is Addition?

Legal Definition
Whatever is added to a man's name by way of title, as additions of estate, mystery, or place. 10 Went. Plead. 871; Salk. 6; 2 Lord Ray. 988; :1 WUS. 244, 5.

2. Additions of an estate or quality are esquire, gentleman, and the like; these titles can however be claimed by none, and may be assumed by any one. In Nash v. Battershy (2 Lord Ray. 986 6 Mod. 80,) the plaintiff declared with the addition of gentleman. The defendant pleaded in abatement that the plaintiff was no gentleman. The plaintiff demurred, and it was held ill; for, said the court, it amounts to a confession that the plaintiff is no gentleman, and then not the person named in the count. He should have replied that he is a gentleman.

3. Additions of mystery are such as scrivener, painter, printer, manufacturer, &c.

4. Additions of places are descriptions by the place of residence, as A. B. of Philadelpliia and thelike. See Bac. Ab. b. t.; Doct. PI. 71; 2 Vin. Abr. 77; 1 Lilly's Reg. 39; 1 Metc. R. 151.

5. At common law there was no need of addition in any case, 2 Lord Ray. 988; it was, required only by Stat. 1 H. 5. c. 5, in cases where process of outlawry lies. In all other cases it is only a description of the person, and common reputation is sufficient. 2 Lord Ray. 849. No addition is necessary in a Homine Replegiando. 2 Lord Ray. 987; Salk. 5; 1 Wils. 244, 6; 6 Rep. 67.
-- Bouviers Law Dictionary
Legal Definition
Whatever is added to a man's name by way of title or description, as additions of mystery, place or degree. Cowell. In English law, there are four kinds of additions,additions of estate, such as yeoman, gentleman, esquire; additions of degree, or names of dignity, as knight, earl, marquis, duke; additions of trade, mystery, or occupation, as scrivener, pninter, mason, carpenter; and additions of place of residence, as London, Chester, etc.

The only additions recognized in American law are those of mystery and residence. In the law of liens. Within the meaning of the mechanic's lien law, an "addition" to a building must be a lateral addition. It must occupy ground without the limits of the building to which it constitutes an addition, so that the lien shall be upon the building formed by the addition and the land upon which it stands. An alteration in a former building, by adding to its height, or to its depth, or to the extent of its interior accommodations, is merely an "alteration," and not an "addition." Putting a new story on an old buliding is not an addition. Updike v. Skillman. 27 N. J. Law, 132. In French law. A supplementary process to obtain additional information. Guyot, Repert
-- Black's Law Dictionary
Legal Definition
Some title or description written after a man’s name for certainty of identification. See 1 Met. (Mass.) 151.
-- Ballentine's Law Dictionary