MAL comes from a Latin word meaning "bad." A malady is a bad condition--a disease or illness--of the body or mind. Malpractice is bad medical practice. Malodorous things smell bad. And a malefactor is someone guilty of bad deeds.

CATA comes from the Greek kata, one of whose meanings was "down." A catalogue is a list of items puts down on paper, and a catapult is a weapon for hurling missiles down on one's enemies.

PROT/PROTO comes from Greek and has the basic meaning "first in time" or "first formed." Protozoa are one-celled animals, such as amoebas and paramecia, that are among the most basic members of the biological kingdom. A proton is an elementary particle that, along with neutrons, can be found in all atomic nuclei. A protoplanet is a whirling mass of gas and dust that astronomers believe may someday become a planet.

ANTE is Latin for "before" or "in front of." Antediluvian, which describes something very old or outdated, literally means "before the flood"--that is, Noah's Flood. And antebellum literally means "before the war," usually the American Civil War.

ORTHO comes from orthos, the Greek word for "straight," "right," or "true." Orthotics is a branch of therapy that straightens out your stance or posture by providing artificial support for weak joints or muscles. And orthograde animals, such as human beings, walk with their bodies in a "straight" or vertical position.

RECT comes from the Latin word rectus, which means "straight" or "right." To correct something is to make it right. A rectangle is a four-sided figure with straight parallel sides. Rectus, short for Latin rectus musculus, may refer to any of several straight muscles, such as those of the abdomen.

EU comes from the Greek word for "well"; in English words it can also mean "good" or "true." A veterinarian who performs euthanasia is providing a very sick or hopelessly injured animal a "good" or easy death.

DYS comes from Greek, where it means "bad" or "difficult." So dysphagia is difficult swallowing, and dyspnea is difficult or labored breathing. Dysphasia is an inability to use and understand language because of injury to or disease of the brain. Dys- is sometimes close in meaning to dis (see DIS), but try not to confuse the two.

Latin Borrowings