Arc·tu·rus 
(ärk-trəs, -tyr-)
(ärk-trəs, -tyr-)n.
The fourth brightest star in the sky and the brightest star in the constellation Boötes, approximately 36 light years from Earth.
[Middle English, from Latin Arctūrus, from Greek Arktouros : arktos, bear; see tko- in the Appendix of Indo-European roots + ouros, guard (from its position behind Ursa Major); see wer-3 in the Appendix of Indo-European roots.]
- Indo-European root: dhreg-
- Indo-European root: dhreibh-
- Indo-European root: dhreu-
- Indo-European root: dhugəter-
- Indo-European root: dhwer-
- Indo-European root: dhē-
- Indo-European root: dhē(i)-
- Indo-European root: dhēs-
- Indo-European root: dhīgw-
- Indo-European root: dlegh-
- Indo-European root: dn̥ghū-
- Indo-European root: dus-
- Indo-European root: dwo-
- Indo-European root: dyeu-
- Indo-European root: dā-
- Indo-European root: dō-
- Indo-European root: ed-
- Indo-European root: eg
- Indo-European root: eghs
- Indo-European root: egwh-
- Indo-European root: ei-
- Indo-European root: eis-
- Indo-European root: ekwo-
- Indo-European root: el-
- Indo-European root: em-