当番 (とうばん)being on duty; person on duty

being on duty; person on dutynoun (common) (futsuumeishi), nouns which may take the genitive case particle 'no'

当番, its kanji, and other words that share them.Open this graph

Kanji in 当番

当初とうしょbeginning; start
当局とうきょくauthorities; relevant authorities
当時とうじat that time; in those days
当選とうせんbeing elected
当面とうめんcurrent; urgent
担当たんとうbeing in charge (of an area of responsibility); being responsible (for a work role, etc.)
本当ほんとうtruth; reality
当然とうぜんnatural; right
一番いちばんnumber one; first
番組ばんぐみprogram (e.g. TV); programme
番号ばんごうnumber; series of digits
本番ほんばんperformance; take
番手ばんて(yarn) count
二番にばんsecond; number two
出番でばんone's turn; one's shift
番付ばんづけranked list (entertainers, sumo wrestlers, millionaires, etc.)

See how 当番 connects to the rest of Japanese.