マイ, バイ, ひら, ...
sheet of..., counter for flat thin objects or sheets
JLPT2 G6 S8 F911
木# tree/wood + 攵 (stick held in the hand) → *stick*; *whip* → *one by one* (← count one by one with a stick) → *counter* (← inaugurate a count).
[Full Kanji Etymology List]