| Term | Definition | Pronunciation |
| J | joule | |
| jaundice | Yellowing of the skin and eyes due to excessive bilirubin in body | jawn´dis |
| jaw | Bony structure of the mouth consisting of the mandible and the maxilla. | |
| jealous | Fearful of the loss of affection or position. | |
| jejun/o | jejunum (second part of the small intestines) | |
| jejunal | Pertaining to the jejunum | |
| jejunum | Part of the small intestine, connecting the duodenum to the ileum. | |
| jerk | A sudden involuntary movement. | |
| JOD | juvenile onset diabetes | |
| joint capsule | The sac surrounding a joint. It is composed of an outer fibrous articular capsule and an inner synovial membrane. | |
| joints | The points of connection between the ends of certain bones. Also known as articulations | |
| JRA | juvenile rheumatoid arthritis | |
| jt. | joint | |
| jug- | yoke | |
| jugular veins | Large veins in the neck which return blood from the brain, face, and neck to the heart. Each side of the neck has two jugular veins, external and internal. | |
| juxta- | near, close | |
| JVD | jugular venous distention | |
| JVP | jugular venous pulse | |