季子 is read as きし (kishi) and means last child.
きし
kishi
きご
seasonal word (in haiku)
きかん
quarterly publication
きせい
degenerate age
きだい
きがさなり
overlapping seasonal words
きまつ
end of the season
きこう
season
きしゅん
late spring
きしゅう
end of autumn
きか
end of summer
きよせ
dictionary of seasonal words (for haiku and haikai)
ふたご
twins