"One example of a word using xero- is xerosis which refers to a dryness, as of the skin, eyes, or mucous membranes."
2. Nothing at all: "The medical researchers are striving to reduce the mortality rate to zero."
3. The point from which the graduation figures of a scale begins: "On the Celsius scale, zero (0°), is the temperature of melting ice, equivalent to 32° on the Fahrenheit scale."
4. A person who is not important, interesting, popular, etc.: "Wiley's new girlfriend is a real zero (loser)."
"The math teacher is trying to zero in on why Gina can't comprehend her simple math assignment."2. To set a measuring device; such as, a scale so it reads 0: "Please zero the scale before you try to weigh the produce (potatoes, onions, etc.)."
The new skin cream had zero effect on the xerosis on his hands; so, he had to go see the dermatologist for a different prescription.