1	
avoirdupois (ˌævəRdəˈpɔɪz). Forms: 4 auoirdepeise, auer de peis,
4–7 avoir de pois, 5 haberdepase, 6 auerdepaise, auer de poiz,
haberdepoys, -poise, 6–7 hauer de pois, haberde-pois, 7 averdepois,
aver-, haberdupois(e, haverdupois(e, 8 hauer-du-pois, 7– avoirdupois.
[A recent corrupt spelling of avoir-de-pois, in early OF. and
AF. aveir de peis `goods of weight,' f. OF. avoir, aveir, property,
goods, aver, de of, pois, peis (= Pr. pes, pens, It. peso):—L.
*pēsum, pensum, weight.  The first word had the variant forms
of the simple aver, and the pronunciation remains ˈaver; the
Norman peis was from 1300 varied with, and c 1500 superseded
by, the Parisian pois.  The best modern spelling is the 17th
c. averdepois; in any case de ought to be restored for du, introduced
by some ignorant `improver' c 1640–1650.] 

  †1.  Merchandise sold by weight.  Obs.  (c 1600.)
  c1300 E.E. Poems (1862) 154 Ʒur gret packes of draperie, auoir-depeise,
and ʒur wol sackes. 1388 Wyclif Ezek. xxvii. 16 Thei settiden
forth in thi marcat gemme, and purpur..and cochod, ether auer
de peis [1382 chodchod, that is, precious marchaundise]. [1392
Act 16 Rich. II, i. §2 Toutz marchants..qe achater ou vendre
voillont bledz, vinz, avoir de pois, char, pesson, & toutz autres
vivres & vitails.] 1502 transl. in Arnold Chron. (1811) 34 Cornes,
wynes, auerdepaise, flesh, fishe, or odur vitayles. 1598 Hakluyt
Voy. I. 137 To exercise other marchandises, as of Hauer de pois,
and other fine wares, as sarcenets, lawnes, cindalles, and silke.
1618 Pulton tr. Act 27 Edw. III, Staple x, That Wools, and all
manner auoir de pois, be weighed by the ballance. 1691 Blount
Law Dict., Avoir du Pois..signifies such Merchandises as are
weighed by this weight, and not by Troy-weight.

  2.  (More fully avoirdupois weight) The standard system of
weights used, in Great Britain, for all goods except the precious
metals, precious stones, and medicines.The a. pound contains
7000 grains.  The a. weight of the United States agrees with
that of Great Britain in the pound, ounce, and dram; but the
hundredweight contains in U.S. 100, in G.B. 112 lbs., and the
ton of 20 cwt. differs accordingly. 
  1485 Inv. in Ripon Ch. Acts 367, j par balance cum ponderibus
de haberdepase. 1532–3 Act 24 Hen. VIII, iii, Lawfull weyght,
called haberdepois. 1543 Recorde Gr. Artes (1575) 202 An other
waight called Haberdepoise, in whiche 16 ounces make a pounde.
1594 Plat Jewell-ho. iii. 7 Vveightes that may agree vvith the
auer de poiz. 1619 Dalton Countr. Just. lxv. (1630) 143 In this
Averdepois weight..112 pounds make a hundred weight. 1631 R.
Brathwait Whimzies 16 A trite discourse of weights and measures:
most ponderously dividing them into troy and averdepois. 1647
Ward Simp. Cobler (1843) 39 Weigh Rules by Troyweight, and not
by the old Haber-du-pois. 1650 B. Discollim. 16 Weighed..at the..publick
beam..not at..every Shop-keeper's Aver-du-pois. 1656 W. Dugard
Gate Lat. Unl. §536 Avoir-du-pois, wherewith wares are bought
and sold. 1667 E. King in Phil. Trans. II. 450, 49 ounces (Haver
de pois weight) of blood. 1669 Boyle Cont. New Exp. i. xxxiii.
(1682) 112 Haberdupoise weight. 1701 J. Jones in A. J. Ellis
E.E. Pron. i. iii. 220, h may be sounded in halleluiah, habiliment,
hauer-du-pois, etc. 1755 Phil. Trans. XLIX. 184 So great a weight
as twenty-six pounds avoirdupoize. 1806 Vince Hydrost. ii. 21
A cubic foot of rain water weighs 1000 ounces avoirdupoise. 1831
Carlyle Sart. Res. ii. viii, The weakest can stand under thirty
stone avoirdupois.

  3.  Weight; degree of heaviness.  (Common in U.S.)
  1597 Shakes. 2 Hen. IV, ii. iv. 276 The weight of an hayre
will turne the Scales betweene their Haber-de-pois. 1680 Hon.
Cavalier 26 To make it more than Aver-du-pois. 1883 Atl. Monthly
May (Football), Avoirdupois and strength are at a premium for
rushing, blocking, and tackling.

2	
avoirdupois (as prec.), v. rareⁱ. [f. the n.] 

  To have the avoirdupois weight of, to weigh. 
  1854 Badham Halieut. 231 A huge African fish..has been known
to avoirdupoise one hundred and forty pounds.