"MW creu cannot be from *krū- (we would expect MW *kri, cf. ki < *kū 'dog'), but it may be from *kruwo-, a thematicized form, generalized from the oblique stem of the PCelt. root-noun (cf. PIE Gen. sg. *ḱruh₂-os)." (RM).
Robert Beekes (with the assistance of Lucien van Beek). Etymological Dictionary of Greek. Indo-European Etymological Dictionaries Online. Edited by Alexander Lubotsky. Brill. Brill Online.
Dictionary of the Irish language: based mainly on old and middle Irish materials. (1913-1976). Dublin: Royal Irish Academy. Online at: http://edil.qub.ac.uk/dictionary/search.php
Matasović, Ranko. Etymological Dictionary of Proto-Celtic. Indo-European Etymological Dictionaries Online. Edited by Alexander Lubotsky. Brill. Brill Online: http://iedo.brillonline.nl.ludwig.lub.lu.se/dictionaries/content/proto-celtic/index.html
Cornish Language Partnership online dictionary http://www.cornishdictionary.org.uk/
Ó Dónaill, Niall & De Bhaldraithe, Tomás (red.) (1977). Foclóir Gaeilge-Béarla. Baile Átha Cliath: An Rún.
Robert Farren, PIE culture words collection, 2017
WN59, WN63, WN69, WN79
Any ancestors and descendants of the selected element are shown in the graph, but siblings and cousins are not.
The element in question is marked in green.
When the etymological tree is displayed in hierarchical style, the nodes can be repositioned manually only within their level.
(Note that the node configuration is not saved in any way.)
The graph as a whole can be zoomed in on by scrolling and can be enlarged by dragging the right-lower corner.
Left-click on a node or edge to show additional information and links. In some browsers, the graph may be savable as an image when right-clicking on it.
This map shows the etymological links in a geographic context.