Hygro is defined as moisture.
An example of hygro is hygrometer, which measures the amount of moisture in the air.
wet, moisture: hygrometer
also, before a vowel, hygr-
Origin of hygro-; from Classical Greek hygros, wet, moist: see humor
Moisture; humidity: hygroscope.
Origin of hygro-From Greek hugros, wet, moist.
= English words prefixed with hygro-
From the Ancient Greek ὑγρός (hugros, “wet”, “moist”).