乳突窦 rǔ tū dòu

DEFINITIONS

  1. mastoid antrum (bones at the back of tympanic chamber)

CHARACTERS

乳 rǔ
HSK 6
breast, nipples; milk, suckle
突 tū
HSK 3
suddenly, abruptly, unexpectedly
窦 dòu surname; hole, burrow; corrupt