root

Etymology 1

From Middle English rote, root, roote (“the underground part of a plant”), from late Old English rōt, from Old Norse rót (Icelandic rót), from Proto-Germanic *wrōts, from Proto-Indo-European *wréh₂ds (“root”); Doublet of wort, radish, and radix.

noun

1. The part of a plant, generally underground, that anchors and supports the plant body, absorbs and stores water and nutrients, and in some plants is able to perform vegetative reproduction.
   This tree's roots can go as deep as twenty metres underground.
   A root caught Ulot's left foot and he almost fell. 1981, Frank Herbert, God Emperor of Dune, →OCLC, page 6
2. A root vegetable.
3. The part of a tooth extending into the bone holding the tooth in place.
   Root damage is a common problem of overbrushing.
4. The part of a hair under the skin that holds the hair in place.
   The root is the only part of the hair that is alive.
5. The part of a hair near the skin that has not been dyed, permed, or otherwise treated.
   He dyed his hair black last month, so the grey roots can be seen.
6. (figurative) The primary source; origin.
   The love of money is the root of all evil.
   They were the roots out of which sprang two distinct people. , Book 1
   Phallicism was, therefore, at the root of all religion, and was definitely the opponent of evil and darkness. 1936, Rollo Ahmed, The Black Art, London: Long, page 160
7. (aviation) The section of a wing immediately adjacent to the fuselage.
8. (engineering) The bottom of the thread of a threaded object.
   The root diameter is the minor diameter of an external thread and the major diameter of an internal one.
9. (arithmetic) Of a number or expression, a number which, when raised to a specified power, yields the specified number or expression.
   The cube root of 27 is 3.
10. (arithmetic) A square root (understood if no power is specified; in which case, "the root of" is often abbreviated to "root").
    Multiply by root 2.
    1899, Dante Gabriel Rossetti (transl.), The New Life (La Vita Nuova) of Dante Alighieri, Siddall edition, page 122. The number three is the root of the number nine; […] being multiplied merely by itself, it produceth nine, as we manifestly perceive that three times three are nine.
11. (mathematical analysis) A zero (of an equation).
    Holonym: kernel
12. (graph theory, computing) The single node of a tree that has no parent.
13. (linguistic morphology) The primary lexical unit of a word, which carries the most significant aspects of semantic content and cannot be reduced into smaller constituents. Inflectional stems often derive from roots.
    Coordinate term: stem
    In ſo moche that if any verbe be of the thyꝛde coniugation / I ſet out all his rotes and tenſes[…] 18 July 1530, Iohan Palſgrave, “The Introduction”, in Leſclarciſſement de la langue francoyſe[…], London: Richard Pynſon, Iohan Haukyns, →OCLC, page 32; reprinted as Lesclarcissement de la langue françoyse, Genève: Slatkine Reprints, 1972
    A considerable number of derived nominals, especially thematic nouns, also exhibited o-grade roots. 2006, Donald Ringe, From Proto-Indo-European to Proto-Germanic (A Linguistic History of English; 1), Oxford: Oxford University Press, page 12
14. (linguistics) A word from which another word or words are derived.
15. (music) The fundamental tone of any chord; the tone from whose harmonics, or overtones, a chord is composed.
16. The lowest place, position, or part.
    the roots of the mountains 1812, Robert Southey, Omniana
17. (computing) In UNIX terminology, the first user account with complete access to the operating system and its configuration, found at the root of the directory structure; the person who manages accounts on a UNIX system.
    I have to log in as root before I do that.
18. (computing) The highest directory of a directory structure which may contain both files and subdirectories.
    I installed the files in the root directory.
19. (slang) A penis, especially the base of a penis.

verb

1. To grow roots; to enter the earth, as roots; to take root and begin to grow.
   The cuttings are starting to root.
   Some old, underfired clay pantiles might be damaged by button mosses rooting in cracks and fissures. But most post-war tiles are hard enough to withstand a bit of moss growth. 26 October 2014, Jeff Howell, “Is the Japanese knotweed threat exaggerated? Our troubleshooter calls for calm about Japanese knotweed in the garden – and moss on the roof [print version: Don't panic about an overhyped invasion, 25 October 2014, p. P13]”, in The Daily Telegraph (Property)
2. To prepare, oversee, or otherwise cause the rooting of cuttings.
   We rooted some cuttings last summer.
3. To be firmly fixed; to be established.
   If any irregularity chanced to intervene and to cause misapprehensions, he gave them not leave to root and fasten by concealment. 1823, Gilbert Burnet, The Life of Sir Matthew Hale, Knt., Sometime Lord Chief Justice of His Majesty's Court of King's-Bench
   Massacres that take place during war often seem to be rooted in irrational emotion. October 15 2020, Frank Pasquale, “‘Machines set loose to slaughter’: the dangerous rise of military AI”, in The Guardian
4. (computing slang, transitive) To get root or privileged access on a computer system or mobile phone, often through bypassing some security mechanism.
   We rooted his box and planted a virus on it.
   I want to root my Android phone so I can remove the preinstalled crapware.

Etymology 2

From Middle English wrōten (“to dig with the snout”), from Old English wrōtan, from Proto-Germanic *wrōtaną (“to dig out, to root”). Related to Old English wrōt (“snout; trunk”). Loss of initial w- probably due to influence from the related noun (Etymology 1).

verb

1. (transitive, intransitive) To turn up or dig with the snout.
   A pig roots the earth for truffles.
   Such tunges ſhuld be torne out by the harde rootes, c. 1515–1516, published 1568, John Skelton, Againſt venemous tongues enpoyſoned with ſclaunder and falſe detractions &c.
2. (by extension) To seek favour or advancement by low arts or grovelling servility; to fawn.
3. (intransitive) To rummage; to search as if by digging in soil.
   rooting about in a junk-filled drawer
4. (intransitive) Of a baby: to turn the head and open the mouth in search of food.
   When your baby is rooting, his head will turn to the side and he will open and close his mouth. If you put your finger in your baby's hand, she has a grasping reflex that makes her curl her fingers around yours and hold on. 2016, Rachel Waddilove, The Baby Book: How to enjoy year one: revised and updated, page 179
5. (transitive) To root out; to abolish.
6. (Australia, New Zealand, Ireland, vulgar, slang) To sexually penetrate.

noun

1. (Australia, New Zealand, vulgar, slang) An act of sexual intercourse.
   Fancy a root?
2. (Australia, New Zealand, vulgar, slang) A sexual partner.

Etymology 3

Possibly an alteration of rout (“to make a loud noise”), influenced by hoot.

verb

1. (intransitive, with "for" or "on", US) To cheer (on); to show support (for) and hope for the success of. (See root for.)
   I'm rooting for you, don't let me down!
   Let me root, root, root for the home team, 1908, Jack Norworth, Take Me Out to the Ball Game