olemus
(4a) n-es juur arvust a on arv, mille n-es aste on arv a
Wiktionary:
8. (arithmetic) of a number or expression, a number which, when raised to a specified power, yields the specified number or expression
Hyponyms: cube root, functional root, square root
The cube root of 27 is 3.
9. (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.

(4b) polünoomi juur = polünoomi nullkoht
Wiktionary:
10. (mathematical analysis) a zero (of an equation)

(4c) juurpuu eritipp
Wiktionary:
11. (graph theory, computing) the single node of a tree that has no parent

(4d) hierarhia kõrgeim tase
Wiktionary:
17. (computing) the highest directory of a directory structure which may contain both files and subdirectories
I installed the files in the root directory.

(4e) morfoloogiliselt jagamatu sõnaosa
Wiktionary:
12. (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

(4f) taime osa
Wiktionary:
1. he 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