▪ I. molar, a.1 and n.
(ˈməʊlə(r))
Also 7 molare, and 7–8 pl. in L. form molares.
[ad. L. molār-is belonging to a mill (n. millstone, grinder tooth), f. mola a millstone: see -ar1. Cf. F. molaire (16th c.); also AF. dentz moellers (Britton).]
A. adj.
1. Grinding, serving to grind. a. spec. Applied to the back-teeth or grinders of mammals, and the flat or rounded grinding teeth of certain fishes.
| 1626 Bacon Sylva §752 The Back-Teeth, which we call the Molar-Teeth, or Grinders. a 1661 Fuller Worthies, Cheshire (1662) i. 172 How necessary these [mill stones] are for mans sustenance, is proved by the painful experience of such aged persons, who wanting their Molare Teeth must make use of their Gums for Grinders. 1728 Bailey, Molar Teeth (i.e. Grinders), the five outmost Teeth on either side of the Mouth. 1871 Darwin Desc. Man. I. i. 36 It appears as if the posterior molar or wisdom-teeth were tending to become rudimentary in the more civilised races of man. 1888 Rolleston & Jackson Anim. Life 12 The number of molar teeth is greater in the Hare and Rabbit than in any other Rodents. |
| fig. 1831 Syd. Smith Wks. (1859) II. 219/2 The majority of the new members will be landed gentlemen: their genus is utterly distinct from the revolutionary tribe; they have Molar teeth; they are destitute of the carnivorous and incisive jaws of political adventurers. |
b. gen.
| 1844 Civil Engin. & Arch. Jrnl. VII. 401/2 The peculiar mechanical power which streams employ in forming their channels by the operation of cataracts,..the molar or grinding process, most common in mountainous countries. |
2. Of or pertaining to a molar-tooth. molar forceps (see quot. 1884).
| 1831 R. Knox Cloquet's Anat. 599 At the back part, between the masseter and buccinator muscles, are two small bodies formed of the assemblage of these follicles. They are designated by the name of Molar Glands, because the orifice of their excretory duct is situated opposite the last molar tooth. 1884 Knight Dict. Mech. Suppl. 613/2 Molar Forceps, heavy forceps for extracting the molars; or cowhorn forceps for eradicating roots when the crowns have decayed below the alveolar process. 1891 Syd. Soc. Lex., Molar glands. |
3. Ent. Of or pertaining to a mola.
| 1879 Wood-Mason in Trans. Ent. Soc. Lond. 152 In..other ‘Rove-beetles’,..no molar process is developed. Ibid., The molar branch of the jaws in Blatta and Machilis. |
4. Path. Of the nature of a mola or false conception.
| 1822–34 Good's Study Med. (ed. 4) IV. 186 Simulating pregnancy, from molar concretions. 1891 in Syd. Soc. Lex. |
B. n.
1. A molar or grinding tooth; a grinder; spec., a true molar, a molar tooth in the adult which is not preceded by a deciduous or milk-molar. false molar, a pre-molar; a molar tooth which has replaced a deciduous or milk-tooth.
| 1541 [see dual n. 2]. 1671 J. Webster Metallogr. ix. 140 Two or three of the molares or grinding teeth of an old Cow. 1767 Phil. Trans. LVII. 465 None of the molares, or grinding teeth of elephants, are discovered with these tusks. 1834 M{supc}Murtrie Cuvier's Anim. Kingd. 50 The canini have two roots, which causes them to partake of the nature of false molars. 1855 W. S. Dallas in Syst. Nat. Hist. II. 494 The true molars are furnished with sharply tubercular crowns. 1881 Mivart Cat 29 Behind the third premolar is an exceedingly small tooth, which is called a true molar. |
2. Ichthyol. A tooth which has a rounded or convex or a flat surface.
| 1880 Günther Fishes 344 In all the species [sc. of Myliobatidæ] the dentition consists of perfectly flat molars, forming a kind of mosaic pavement. Ibid. 406 Jaws [sc. of Sargina] with a single series of incisors in front, and with several series of rounded molars on the side. |
3. Ent. One of the thick internal processes with a grinding surface found on and near the base of the mandibles of many insects.
| 1892 J. B. Smith in Trans. Amer. Entom. Soc. XIX. 84 Another of the basal pieces,..I propose to call the molar, or grinder... In the present species the molars are ridged and dissimilar. |
▪ II. molar, a.2
(ˈməʊlə(r))
[f. L. mōlēs mass; see -ar1; cf. mole n.3]
a. Pertaining to mass; acting on or by means of large masses of matter. Often contrasted with molecular.
| 1862 H. Spencer First Princ. ii. v. §55 (1875) 181 The molar motion which disappears when a bell is struck by its clapper, reappears in the bell's vibrations. 1871 Tyndall Fragm. Sci. (1879) I. xii. 360 This cleavage is..molar, not molecular. 1903 F. W. H. Myers Human Personality II. 509 This apparently molar world consists..of at least two interpenetrating environments, molecular and etherial. |
b. Psychol. (See quot. 1932.)
| 1925 C. D. Broad Mind & its Place xiv. 616, I will lump together all such changes under the name of ‘molar behaviour’, as contrasted with ‘molecular behaviour’. 1932 E. C. Tolman Purposive Behavior I. i. 7 On the one hand, he [sc. J. B. Watson] has defined behavior in terms of its strict physical and physiological details, i.e., in terms of receptor-process, conductor-process, and effector-process per se. We shall designate this as the molecular definition of behavior. And on the other hand, he has come to recognize..that behavior..is more than and different from the sum of its physiological parts. Behavior..has descriptive and defining properties of its own. And we shall designate this latter as the molar definition of behavior. 1946 C. Morris Signs, Lang. & Behavior ii. 55 Behavioristics naturally attempts to supplement its description of behavior in molar or macroscopic terms. 1971 Jrnl. Gen. Psychol. LXXXIV. 157 Attention has been concentrated on those papers which do not support the notion that single cell behavior is reflected in molar behavior. |
▪ III. molar, a.3 Physical Chem.
(ˈməʊlə(r))
[f. mole n.7 + -ar1.]
a. Of or pertaining to one mole of a substance; = molal a. a, molecular a. 1 a.
| 1902 A. Findlay tr. Ostwald's Princ. Inorg. Chem. vi. 89 The ratio of the weight of a given gas to that of an equal volume of the normal gas under the same conditions, is called its molecular weight or its molar weight. Since the former name has been derived from certain hypothetical notions regarding the constitution of the gases, notions which are not essential to the actual facts, we shall give preference to the name molar weight although, at present, the other is still the one most used. 1906 [see gramme-molecular adj. s.v. gram2 b]. 1946 J. R. Partington Gen. & Inorg. Chem. i. 7 This is called the molar volume Vm, and Avogadro's hypothesis shows that it is the same for all substances. 1962 P. J. & B. Durrant Introd. Adv. Inorg. Chem. xi. 303 If both sides of the equation are multiplied by the molecular weight M and divided by the density ρ, (k - 1)M/(k + 2)ρ = 4/3 πNα = PM where N is Avogadro's number and PM is known as the molar polarisation. Ibid. 307 A quantity R known as the molar refraction. 1967 Oceanogr. & Marine Biol. V. 154 Some normal calcite and a small amount of dolomite with a molar ratio of CaCO3:MgCO3 of 1·1:1 were also present. |
b. Of a solution: containing one mole, or a specified number of moles, of solute per litre of solution. Of a concentration: expressed in terms of these quantities. Cf. molal a. b.
| 1927 C. J. Engelder Textbk. Elem. Qualitative Analysis 1. 4 Thus 34·468 grams of HCl or 58·46 grams of NaCl, dissolved and diluted to one liter, are molar solutions of these compounds. 1946 Nature 26 Oct. 585/1 The molar concentration required to produce a given effect is approximately one third that of the preceding member [of a homologous series]. 1970 Man. Symbols & Terminol. Physicochem. Quantities & Units (I.U.P.A.C.) 12 A solution with a concentration of 0·1 mol dm-3 is often called a 0· 1 molar solution. 1971 G. D. Christian Analytical Chem. i. 9 A one-molar solution of silver nitrate and a one-molar solution of sodium chloride will react on an equal-volume basis. |
Hence moˈlarity, the molar concentration of a solution.
| 1931 J. C. Ware Analytical Chem. i. i. 3 Where the solubility is very small, the molarity and the molality of the solution will be approximately the same. 1951 M. A. Paul Princ. Chem. Thermodynamics vii. 388 The molarity of a given solution evidently varies in general with temperature. 1970 Man. Symbols & Terminol. Physiochem. Quantities & Units (I.U.P.A.C.) 12 Concentration is sometimes called ‘molarity’ but this name is both unnecessary and liable to cause confusion with molality and is therefore not recommended. 1973 Block & Holliday Mod. Physical Chem. ix. 203 In general, molarities cannot easily be related either to mole fraction or to molality, unless the changes in volume on dissolution are either negligible or can be allowed for. |