xylophone noun A percussion instrument with wooden bars of different lengths that are struck with mallets to produce musical notes. The music teacher handed each child a mallet and let them take turns playing the xylophone. + xenophobia noun A strong dislike, fear, or distrust of people from other countries or cultures. The rise in xenophobia led to increased hostility toward recent immigrants. + X-ray noun A form of high-energy electromagnetic radiation used to produce images of the inside of the body or solid objects. The doctor ordered an X-ray to check whether the bone in her wrist was broken. + oxygen noun A colorless, odorless gas in the air that humans and animals need to breathe in order to survive. Firefighters carried extra tanks of oxygen so they could breathe safely inside the smoke-filled building. + exit noun A way out of a building, vehicle, or enclosed space. Fire regulations require every classroom to have a clearly marked exit. + exam noun A formal test of knowledge or skill, especially one taken at school or for a qualification. I stayed up late reviewing my notes before the chemistry exam. + excellent adjective Extremely good; of outstanding quality, skill, or character. The chef prepared an excellent meal that impressed every guest at the table. + exercise noun Physical activity done to improve health, strength, or fitness. Doctors recommend at least thirty minutes of exercise most days of the week. + extreme adjective Very great in degree, intensity, or severity; far beyond what is usual or moderate. The desert experiences extreme temperatures, from freezing nights to scorching afternoons. + complex adjective Having many connected parts or details that can be difficult to understand. The map shows a complex network of underground passages. + fax noun A document sent electronically over telephone lines, or the machine used to send and receive it. The office still keeps an old fax machine for a few clients who prefer it. + relax verb To become less tense, anxious, or rigid; to rest and ease physical or mental strain. After the exam, she finally relaxed with a cup of tea and her favorite show. + taxi noun A car with a driver that can be hired to take passengers to a destination for a fare. We hailed a taxi outside the station to get to the hotel quickly. + zebra noun An African wild animal related to the horse, recognized by its distinctive black-and-white striped coat. A herd of zebra grazed peacefully near the watering hole at sunset. + zero number The number 0, representing no quantity or amount, and the point separating positive from negative numbers. The temperature dropped to zero degrees overnight, and the pond froze solid. + zigzag noun A line or path that turns sharply from side to side in a series of alternating angles. The hiking trail followed a zigzag up the steep face of the mountain. + zipper noun A fastening device with two rows of interlocking teeth joined or separated by a sliding tab. The zipper on her jacket got stuck halfway up in the cold wind. + dizzy adjective Feeling unsteady, faint, or as if everything is spinning around. She felt dizzy after standing up too quickly from the couch. + puzzle noun A game or problem designed to test knowledge or ingenuity by requiring a solution. He spent the rainy afternoon assembling a thousand-piece jigsaw puzzle. + freeze verb To become solid because of low temperature, or to stop moving suddenly. The pond will freeze completely if the temperature stays below zero all week. + breeze noun A gentle, light wind. A cool breeze drifted through the open window on the summer evening. + sneeze verb To expel air suddenly and forcefully through the nose and mouth, usually involuntarily. The dusty attic made her sneeze several times before she found the old photos. + zone noun An area or region distinguished from surrounding areas by a particular feature, use, or purpose. The city council designated the waterfront as a pedestrian-only zone. + size noun The physical dimensions, extent, or overall scale of something, often measured or compared to others. The store didn't have his size, so he ordered the shoes online instead. + prize noun An award given to the winner of a competition, contest, or lottery. She won first prize for her painting at the county fair. + amaze verb To fill someone with great surprise, wonder, or astonishment. The magician's final trick amazed everyone sitting in the audience. + citizen noun A person who legally belongs to a particular country and has the rights and duties that come with it. She became a citizen of Canada after living there for six years. + zoology noun The scientific study of animals, including their structure, behavior, classification, and distribution. She switched her major to zoology after volunteering at a wildlife rehabilitation center. + zephyr noun A soft, gentle breeze, especially one coming from the west. A cool zephyr drifted across the meadow as the sun began to set. + buzzard noun A large bird of prey known for soaring in wide circles while searching for food. A lone buzzard circled slowly above the sunbaked field at noon. +