Final answer:
The term that means 'cheek' is 'sialo', which refers to the salivary glands in the cheeks. This is evident during actions like sucking on a straw or blowing air.
Step-by-step explanation:
The combining form that means cheek is sialo. This term refers to the salivary glands which are located in the cheeks. Movements of the cheeks, such as the lateral movement involved when sucking on a straw or compressing air in the mouth while blowing, are functions that demonstrate the flexibility and use of the cheek muscles.