Yashan
From Halachipedia
Definition
In the Torah it says "You must not eat any bread, or roasted or new grain, until the very day you bring this offering to your God. This is to be a lasting ordinance for the generations to come, wherever you live." [1] Based on this verse, there is a concept derived called "Yoshon" (literally meaning "old") such that any grain product that is harvested before the 16th of Nissan cannot be eaten until after the passage of that date, which then transforms the food from the prohibited status of Chodosh to the permitted status of Yoshon.
In the Diaspora
There is a debate in the Gemara regarding the applicability of the prohibition to the diaspora. [2] Nearly all the Rishonim rule that the prohibition applies equally to the diaspora [3]
Other Spellings
Yoshon; Yoshen
