poo·ka 
(pkə)
(pkə)n.
A mischievous spirit in Irish folklore.
[Irish púca, from Old Irish, probably from Old English pūca, goblin.]
- cosmic string
- cosmid
- cosmo
- cosmo-
- cosmochemical
- cosmochemist
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- cosmogonically
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- cosmological
- cosmological constant
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- cosmonaut