olemus
puu koos selle puu juureks oleva huvialuse tipuga;
juurpuu tipud saab jagada hierarhiatasemetesse
vastavalt nende kaugusele juurest,
juur on hierarhia kõrgeim tase

ISO/IEC 11770:
sidus atsükliline graaf piiritletud eritipuga, st juurega
= connected, acyclic graph with an identified special node, the root node

ISO/IEC 20944:
andmestruktuur, millel on ainult üks juurtipp ning mis
sisaldab tippe, mis on ühendatud hierarhiliselt, nii et
igal tipul ei ole üle ühe ematipu
= data structure containing nodes that are linked together hierarchically with at most one parent node for each node, and with only one root node

piltlikult
https://www.tutorialspoint.com/discrete_mathematics/images/rooted_tree.jpg

http://slideplayer.com/slide/8471551/26/images/11/Rooted+Tree+A+rooted+tree+is+a+tree+in+which+one+vertex+has+been+designated+as+the+root+and+every+edge+is+directed+away+from+the+root..jpg

ülevaateid
https://en.wikipedia.org/wiki/Tree_(graph_theory)#Rooted_tree

http://mathworld.wolfram.com/RootedTree.html

http://courses.ics.hawaii.edu/ReviewICS241/morea/trees/Trees-QA.pdf

https://medium.freecodecamp.org/all-you-need-to-know-about-tree-data-structures-bceacb85490c