The grandfather's share when there are more heirs than the primary known configuration (husband, sister, grandfather).
Chapter on Inheritance of the Grandfather
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
If the number of sisters increases beyond the primary case, the paternal grandfather is allotted his fixed share of one-sixth, and the rest is distributed to the other heirs (the husband and the sisters).