Final answer:
The combining form 'ichthy/o' signifies scaly, dry skin and is used in medical terms like 'ichthyosis' to describe conditions with dry, scaly skin.
Step-by-step explanation:
The combining form that means scaly, dry is ichthy/o. In medical terminology, this prefix is derived from the Greek word 'ichthys' which means fish, referring to the dry, scaly appearance of the skin that is reminiscent of fish scales. It is commonly used in terms for conditions that involve abnormally dry, thickened, scaly skin such as ichthyosis.