Often in genealogy a researcher encounters an archaic medical term used for the cause of death, or perhaps in a journal or family correspondence, this list is intended to aid with interpreting those terms.

Abasia - Inability to walk or stand, caused by hysteria.
Ablepsy - Blindness, also Ablepsia, Abopsia.
Abscess - A localized collection of pus buried in tissues, organs, or confined spaces of the body, often accompanied by swelling and inflammation and frequently caused by bacteria. The brain, lung, or kidney (for instance) could be involved. See boil.
Accouchment - childbirth, the period after childbirth.
Acute - (adj.) disease of sudden onset, severe, not chronic.
Addison's disease - A disease characterized by severe weakness, low blood pressure, and a bronzed coloration of the skin, due to decreased secretion of cortisol from the adrenal gland. Dr. Thomas Addison (1793-1860), born near Newcastle, England, described the disease in 1855. Synonyms: Morbus addisonii, bronzed skin disease.
Aegrotat - Is sick from.
Aegrotantem - Sickness, illness.
Ague - Malarial Fever; Malarial or intermittent fever characterized by paroxysms (stages of chills, fever, and sweating at regularly recurring times) and followed by an interval or intermission whose length determines the epithets: quotidian, tertian, quartan, and quintan ague (defined in the text). Popularly, the disease was known as "fever and ague," "chill fever," "the shakes," and by names expressive of the locality in which it was prevalent--such as, "swamp fever" (in Louisiana), "Panama fever," and "Chagres fever."
Ague-cake - A form of enlargement of the spleen, resulting from the action of malaria on the system.
American plague - Yellow fever.
Anasarca - Generalized massive edema. see dropsy.
Anchylosis/ankylosis - Abnormal stiffening and immobility of a joint by fusion of the bones.
Angina - Pain in chest brought on by exertion; intense constricting pain especially of the throat, can lead to suffocation; quinsy.
Aphonia - Laryngitis.
Aphtha/aphthae - see thrush.
Aphthous stomatitis - see canker.
Apoplexy - Paralysis due to stroke.
Ascites - see dropsy.
Asphycsia/Asphicsia - Cyanotic and lack of oxygen.
Asthenia - see debility.
Atrophy - Wasting away or diminishing in size.

Bad Blood - Syphilis.
Bilious fever - A term loosely applied to certain enteric (intestinal) and malarial fevers; Typhoid, malaria, hepatitis or elevated temperature and bile emesis /fever due to a liver disorder, See typhus.
Biliousness - Jaundice associated with liver disease; A complex of symptoms comprising nausea, abdominal discomfort, headache, and constipation; formerly attributed to excessive secretion of bile from the liver.
Black plague/death - Bubonic plague.
Black fever - Acute infection with high temperature and dark red skin lesions and high mortality rate.
Black pox - Black Small pox.
Black vomit - Vomiting old (black) blood due to ulcers or yellow fever.
Blackwater fever - Dark urine associated with high temperature.
Bladder in throat - Diphtheria.
Blood poisoning - Bacterial infection; septicemia.
Bloody flux - Bloody stools; dysentry.
Bloody sweat - Sweating sickness.
Boil - An abscess of skin or painful, circumscribed inflammation of the skin or a hair follicle, having a dead, pus-forming inner core, usually caused by a staphylococcal infection. Synonym: furuncle.
Bone shave - Sciatica.
Brain fever - see meningitis, typhus.
Breakbone - Dengue fever.
Bright's disease - Chronic inflammatory disease of kidneys; kiddney disease; glomerulonephritis.
Bronchial asthma - A paroxysmal, often allergic disorder of breathing, characterized by spasm of the bronchial tubes of the lungs, wheezing, and difficulty in breathing air outward, often accompanied by coughing and a feeling of tightness in the chest.
Bronze John - Yellow fever.
Brucellosis - bacterial disease, especially of cattle, causing undulant fever in humans.
Bule - Boil, tumor or swelling.

Cachexy - Malnutrition.
Cacogastric - Upset stomach.
Cacospysy - Irregular pulse.
Caduceus - Subject to falling sickness or epilepsy.
Camp fever - Typhus; aka Camp diarrhea, typhoid fever.
Cancer - A malignant and invasive growth or tumor (especially tissue that covers a surface or lines a cavity), tending to recur after excision and to spread to other sites. In the nineteenth century, physicians noted that cancerous tumors tended to ulcerate, grew constantly, and progressed to a fatal end and that there was scarcely a tissue they would not invade. Synonyms: malignant growth, carcinoma.
Cancrum otis - A severe, destructive, eroding ulcer of the cheek and lip, rapidly proceeding to sloughing. In the last century it was seen in delicate, ill-fed, ill-tended children between the ages of two and five. The disease was the result of poor hygiene acting upon a debilitated system. It commonly followed one of the eruptive fevers and was often fatal. The destructive disease could, in a few days, lead to gangrene of the lips, cheeks, tonsils, palate, tongue, and even half the face; teeth would fall from their sockets, and a horribly fetid saliva flowed from the parts. Synonyms: canker, water canker, noma, gangrenous stomatitis, gangrenous ulceration of the mouth.
Canine madness - Rabies, hydrophobia.
Canker - An ulcerous sore of the mouth and lips, not considered fatal today; herpes simplex Synonym: aphthous stomatitis. See cancrum otis.
Catalepsy - Condition which causes Seizures/trances or unconsciousness.
Catarrh - Inflammation of a mucous membrane, especially of the air passages of the head and throat, with a free discharge. It is characterized by cough, thirst, lassitude, fever, watery eyes, and increased secretions of mucus from the air passages. Bronchial catarrh was bronchitis; suffocative catarrh was croup; urethral catarrh was gleet; vaginal catarrh was leukorrhea; epidemic catarrh was the same as influenza. Synonyms: cold, coryza. Nose and throat discharge from cold or allergy; influenza.
Cerebritis - Inflammation of cerebrum or lead poisoning.
Chilblain - Swelling of extremities caused by exposure to cold and then heat; extremities turn black and itch unbearably.
Childbed - Childbirth.
Child bed fever - Infection following birth of a child; puerperal fever.
Childbirth - A cause given for many female deaths of the century. Almost all babies were born in homes and usually were delivered by a family member or a midwife; thus infection and lack of medical skill were often the actual causes of death.
Chin cough - Whooping cough.
Chlorosis - Iron deficiency anemia; condition of pale or greenish skin, weakness, & dyspepsia.
Cholecystitis - Inflammation of the gall bladder.
Cholelithiasis - Stones of the gall bladder.
Cholera - An acute, infectious disease, endemic in India and China and now occasionally epidemic elsewhere: characterized by profuse diarrhea, vomiting, and cramps. It is caused by a potent toxin discharged by the bacterium Vibrio cholerae, which acts on the small intestine to cause secretion of large amounts of fluid. The painless, watery diarrhea and the passing of rice-water stool are characteristic. Great body-salt depletion occurs. Cholera is spread by feces-contaminated water and food. Major epidemics struck the United States in the years 1832, 1849, and 1866. In the 1830s the causes were generally thought to be intemperance in the use of ardent spirits or drinking bad water; uncleanness, poor living or crowded and ill-ventilated dwellings; and too much fatigue. By 1850 cholera was thought to be caused by putrid animal poison and miasma or pestilential vapor rising from swamps and marshes, or that it entered the body through the lungs or was transmitted through the medium of clothing. It was still believed that it attacked the poor, the dissolute, the diseased, and the fearful, while the healthy, well-clad, well-fed, and fearless man escaped the ravages of cholera.
Cholera infantum - A common, noncontagious diarrhea of young children, occurring in summer or autumn. In the nineteenth century it was considered indigenous to the United States; was prevalent during the hot weather in most of the towns of the middle and southern states, as well as many western areas; and was characterized by gastric pain, vomiting, purgation, fever, and prostration. It was common among the poor and in hand-fed babies. Death frequently occurred in three to five days. Synonyms: summer complaint, weaning brash, water gripes, choleric fever of children, cholera morbus.
Cholera morbus - Characterized by nausea, vomiting, abdominal cramps, elevated temperature, etc. Could be appendicitis
Chorea - Any of several diseases of the nervous system, characterized by jerky movements that appear to be well co-ordinated but are performed involuntarily, chiefly of the face and extremities; convulsions, contortions and dancing. Synonym: Saint Vitus' dance.
Chronic - Persisting over a long period of time as opposed to acute or sudden. This word was often the only one entered under "cause of death" in the mortality schedules. The actual disease meant by the term is open to speculation.
Cold plague - Ague which is characterized by chills.
Colic - Paroxysmal pain in the abdomen or bowels. Infantile colic is benign paroxysmal abdominal pain during the first three months of life. Colic rarely caused death; but in the last century a study reported that in cases of death, intussusception (the prolapse of one part of the intestine into the lumen of an immediately adjoining part) occasionally occurred. Renal colic can occur from disease in the kidney, gallstone colic from a stone in the bile duct.
Confinement - the conclusion of pregnancy; labor and childbirth.
Congestive chills - Malaria.
Consumption - A wasting away of the body; formerly applied especially to pulmonary tuberculosis. The disorder is now known to be an infectious disease caused by the bacterial species Mycobacterium tuberculosis. Synonyms: marasmus (in the mid 19th century), phthisis.
Congestion - An excessive or abnormal accumulation of blood or other fluid in a body part, blood vessel or an organ, like the lungs Congestive chills. Malaria with diarrhea.
Congestive fever - Malaria Corruption Infection.
Convulsions - Severe contortion of the body caused by violent, involuntary muscular contractions of the extremities, trunk, and head. See epilepsy.
Coryza - A cold. see catarrh.
Costiveness - Constipation.
Cramp colic - Appendicitis.
Crop sickness - Overextended stomach.
Croup - Any obstructive condition of the larynx (voice box) or trachea (windpipe), characterized by a hoarse, barking cough and difficult breathing occurring chiefly in infants and children. The obstruction could be caused by allergy, a foreign body, infection, or new growth (tumor). In the early 19th century it was called cynanche trachealis. The crouping noise was similar to the sound emitted by a chicken affected with the pip, which in some parts of Scotland was called roup; hence, probably, the term croup; Laryngitis, diphtheria, or strep throat; a childhood illness. Synonyms: roup, hives, choak, stuffing, rising of the lights.
Cyanosis - Dark skin color; blueness of skin caused by lack of oxygen in blood.
Cynanche - Diseases of throat.
Cystitis - Inflammation of the bladder.