From שָׁבוּעַ (shavúa', “week”) + ־ון (-ón, “suffix indicating a periodical”).
שְׁבוּעוֹן • (shvuón) m (plural indefinite שְׁבוּעוֹנִים, singular construct שְׁבוּעוֹן־, plural construct שְׁבוּעוֹנֵי־)