199. Some roots are used as noun stems: as, #duc-#, N. #dux#, _leader_
(√#duc-#, _lead_); #rēg-#, N. #rēx#, _king_ (√#rēg-#, _guide_);
particularly at the end of a compound: as, #con-iug-#, N. #coniūnx#,
_yoke-fellow_, _spouse_ (#com-#, √#jug-#, _yoke_); #tubi-cin-#, N.
#tubicen#, _trumpeter_ (#tubā-#, √#can-#, _play_).