Nubwo tariki 21 Kamena yitiriwe umunsi mukuru w’ igitunguru mu Bufaransa nta muntu urasobanura impamvu yabyo, gusa iki gihingwa kirubashwe kuko gikoreshwa nk’ imboga cyangwa deseri .
Tariki 21 Kamena yabarwaga nk’ umunsi wa gatatu w’ ukwezi kwitiriwe Messidor kuri kalendari y’ Abarepubulikani (calendrier républicain) mu Bufransa bakawita umunsi w’ igitunguru (le jour de l’oignon) mu rwego rw’ igihugu.
Tariki 21 Kamena, ni umunsi w’ i 172 w’ umwaka tugendeye kuri kalendari ya Geregwari (calendrier grégorien) byumvikane ko hasigaye iminsi 193 kugira ngo umwaka urangire.
Ubusanzwe mu bumenyi bw’ isi(geography) ni umunsi w’ inzibacyuho w’ ibihe , aho ubushuhe bwiganza mu Merekezo y’ Amajyaruguru(Hemisphere Nord ) ndetse n’ ubukonje bukarushaho kuba bwinshi mu Merekezo y’ Amajyepfo(Hemisphere Sud), bityo impeshye nyayo igatangira.
