tuán
=
tu
+
an2:
round / lump / ball / to roll into a ball / to gather / regiment / group / society / classifier for a lump or a soft mass: wad (of paper), ball (of wool), cloud (of smoke)
Mnemonic
Tommy Turtle (tu) inspects the super secret box (囗) in the anthill's kitchen (an2). He's not supposed to open it, but with his super X-ray vision ability (才), he can see that it is filled with balls (团) and dumplings (团).
round / lump / ball / to roll into a ball / to gather / regiment / group / society / classifier for a lump or a soft mass: wad (of paper), ball (of wool), cloud (of smoke)