עַשְׁתֵּי ʻashtêy (H6249)

eleven or (ordinal) eleventh

1) one, eleven, eleventh 1a) one as combined with ten ( H06240)

apparently masculine plural construction of עֶשֶׁת (H6247) in the sense of an afterthought (used only in connection with עָשָׂר (H6240) in lieu of אֶחָד (H259))