root¹ / roōt; roŏt/ • n. 1. the part of a plant that attaches it to the ground or to a support, typically underground, conveying water and nourishment to the rest of the plant via numerous branches and fibers: cacti have deep and spreading roots a tree root. ∎  the persistent underground part of a plant, esp. when fleshy and enlarged and used as a vegetable, e.g., a turnip or carrot. ∎  any plant grown for such a root. ∎  the embedded part of a bodily organ or structure such as a hair, tooth, or nail: her hair was fairer at the roots. ∎  the part of a thing attaching it to a greater or more fundamental whole; the end or base: a little lever near the root of the barrel.2. the basic cause, source, or origin of something: love of money is the root of all evil jealousy was at the root of it | [as adj.] the root cause of the problem. ∎  the essential substance or nature of something: matters at the heart and root of existence. ∎  (roots) family, ethnic, or cultural origins, esp. as the reasons for one's long-standing emotional attachment to a place or community: it's always nice to return to my roots. ∎  [as adj.] (roots) denoting or relating to something, esp. music, from a particular ethnic or cultural origin, esp. a non-Western one: roots music. ∎  (in biblical use) a scion; a descendant: the root of David. ∎  Linguistics a morpheme, not necessarily surviving as a word in itself, from which words have been made by the addition of prefixes or suffixes or by other modification: many European words stem from this linguistic root | [as adj.] the root form of the word. ∎  Mus. the fundamental note of a chord.3. Math. a number or quantity that when multiplied by itself, typically a specified number of times, gives a specified number or quantity: find the cube root of the result. ∎ short for square root. ∎  a value of an unknown quantity satisfying a given equation: the roots of the equation differ by an integer. • v. [tr.] 1. cause (a plant or cutting) to grow roots: root your own cuttings from stock plants. ∎  [intr.] (of a plant or cutting) establish roots: large trees had rooted in the canal bank.2. (usu. be rooted) establish deeply and firmly: vegetarianism is rooted in Indian culture. ∎  (be rooted in) have as an origin or cause: the Latin dubitare is rooted in an Indo-European word. ∎  [tr.] [often as adj.] (rooted) cause (someone) to stand immobile through fear or amazement: she found herself rooted to the spot in disbelief. PHRASES: at root basically; fundamentally: it is a moral question at root.put down roots (of a plant) begin to draw nourishment from the soil through its roots. ∎  (of a person) begin to have a settled life in a particular place.root and branch used to express the thorough or radical nature of a process or operation: root and branch reform of personal taxation.strike at the root (or roots) of affect in a vital area with potentially destructive results: the proposals struck at the roots of community life.take root (of a plant) begin to grow and draw nourishment from the soil through its roots. ∎  become fixed or established: the idea had taken root in my mind.PHRASAL VERBS: root something out (also root something up) dig or pull up a plant by the roots. ∎  find and get rid of someone or something regarded as pernicious or dangerous: a campaign to root out corruption.DERIVATIVES: root·ed·ness n.root·let / -lət/ n.root·like / -ˌlīk/ adj.root·y adj.root² • v. [intr.] (of an animal) turn up the ground with its snout in search of food: stray dogs rooting around for bones and scraps. ∎  search unsystematically through an untidy mass or area; rummage: she was rooting through a pile of papers. ∎  [tr.] (root something out) find or extract something by rummaging: he managed to root out the cleaning kit.• n. [in sing.] an act of rooting: I have a root through the open drawers.PHRASAL VERBS: root for inf. support or hope for the success of (a person or group entering a contest or undertaking a challenge): the whole of this club is rooting for him.root someone on inf. cheer or spur someone on: his mother rooted him on enthusiastically from ringside.