sikaPronunciation: /ˈsiːkə/ (also sika deer)Definition of sika noun a forest-dwelling deer with a greyish winter coat that turns yellowish-brown with white spots in summer. It is native to Japan and SE Asia and naturalized in Britain and elsewhere. Cervus nippon, family Cervidae Origin: late 19th century: from Japanese shikasika in other Oxford dictionaries Definition of sika in the US English dictionary