a. [f. mod.L. centripet-us (Newton) center-seeking + -AL. With mod.L. centrifugus, centripetus, cf. Isid. XII. viii. 9 ‘musca lucipeta, blatta lucifuga est’; heredipeta, lucripeta also occur in L. Cf. mod.F. centripète.]
1. Tending toward the center; the opposite of centrifugal.
a. Centripetal force: a force that draws or impels a body toward some point as a center, and thus acts as a counterpoise to the centrifugal tendency in circular motion; for this the name centripetal tendency is substituted by some.
[1687. Newton, Principia, Defin. v. Vim conatui illi contrariam … Centripetam appello.]
1709. Tatler, No. 43, ¶ 7. Thus the Tangential and Centripetal Forces, by their Counter-struggle, make the Celestial Bodies describe an exact Ellipsis.
1764. Reid, Inquiry, ii. § 9. Centripetal force is put for the cause, which we conceive to be some power or virtue in the centre or central body.
1841–4. [see CENTRIFUGAL 1].
1868. Lockyer, Elem. Astron., 306. Were the centrifugal tendency to cease, the centripetal force would be uncontrolled, and the body would fall upon the attracting mass.
b. fig. and transf.
a. 1711. Ken, Sion, Wks. 1721, IV. 419. They Unwing’d, as swiftly flew the spacious way, By their centripetal connat’ral Force, To their Triune, co-amiable Source.
a. 1763. Shenstone, Ess., 112. Indolence is a kind of centripetal force.
1870. Gladstone, Glean., IV. vi. 202. While centripetal and centrifugal forces are thus engaged in mortal tug.
2. Applied to machines or parts of mechanism that employ centripetal action: as centripetal press, centripetal pump.
1874. Knight, Dict. Mech., Centripetal pump … in one form it is the exact converse of the Barker Mill.
3. Bot. Tending or developing from without toward the center. Centripetal inflorescence, that in which the lowest or outermost flowers blossom first, as in spikes and umbels; also called indeterminate or indefinite.
1870. Hooker, Stud. Flora, 184. Compositæ … Inflorescence a centripetal head of many small flowers.
1880. Gray, Struct. Bot., v. 145. The Indefinite or Indeterminate type of inflorescence has been called Centripetal, because … the evolution is seen to proceed from circumference to centre.
1882. Vines, Sachs’ Bot., 536. The acropetal or centripetal order of succession of the floral leaves.
4. Biol. a. Proceeding from the exterior to the interior or center. b. Of nerves: Conveying an impulse from the periphery to the ‘center’; afferent.
1836. Todd, Cycl. Anat., I. 763/1. The law of centripetal development.
1855. Owen, Skel. & Teeth, 291. As the centripetal calcification proceeds the caps are converted into horn-shaped cones.
1877. Roberts, Handbk. Med. (ed. 3), I. 52. The centripetal or sensory nerves.
