Test your vocabulary skills with a game of flash cards →
alveoli (al-VEE-oh-lye) Alveoli are the small balloonlike sacs in the lungs. Gases are exchanged in the alveoli.
ambulance (AM-byoo-lenss) An ambulance is a specialized vehicle that is used to carry sick or very injured people to the hospital.
annoyed (uh-NOYD) Someone is annoyed when he or she is a little mad or irritated. The teacher was annoyed with Dean.
antibody (AN-tih-bah-dee) An antibody is a protein made by your cells in your immune system. Antibodies fight invading germs.
anxiety (ang-ZY-uh-tee) Anxiety is a feeling of fear or worry. Both children and adults experience anxiety.
apologize (uh-PAWL-oh-jize) To apologize is to say you are sorry for hurting someone. Drew wanted to apologize to Micah for stealing the soccer ball.
apologizes (uh-PAWL-uh-jize-es) When someone apologizes, she says she is sorry. Rachel apologizes to her brother.
appreciate (uh-PREE-shee-ayt) To appreciate something is to like it. A friend might appreciate it if you ask if he or she needs help.
argue (AHR-gyoo) To argue means to disagree with someone about something. The students argue with each other over what book to read.
assess (uh-SESS) To find out or decide the importance of a problem.
bacteria (bak-TEER-ee-uh) Bacteria are tiny living things that are found almost everywhere. Some kinds are helpful, while others cause diseases.
behavior (bee-HAYV-yur) A behavior is something that you do. Kevin’s sighs were a behavior.
biosafety (bye-oh-SAYF-tee) Biosafety is safety relating to biological research. CDC labs have biosafety numbers that indicate the safety measures that should be used in each lab.
bioterrorism (bye-oh-TER-urism) Bioterrorism is the use of a virus or other agent to hurt or kill others. CDC workers are trained to fight bioterrorism.
brag (BRAG) To brag means to talk about something in a boastful way. James’s friends said they would not brag.
brainstorm (BRAYN-storm) To brainstorm means to come together and think of ideas to solve a problem. The family decided to brainstorm ways to save money.
bronchioles (brahng-KEE-uhlz) Bronchioles are smaller tubes that branch off of the right bronchus and left bronchus in the lungs. Alveoli are found at the end of the bronchioles.
bronchus (brahng-KUS) The right bronchus and left bronchus are tubes that branch off of the trachea. They help bring air to the lungs.
calm (KALM) To be calm is to feel relaxed and at peace. Ellie felt calm after she took a deep breath.
carbon dioxide (KAHR-buhn dye-AHK-side) Carbon dioxide is a gas found in the air. The lungs remove carbon dioxide from the body when you exhale.