observational study

A clinical trial which reports on an unfolding situation.

obstetric

(ob-stet-trick)

Relating to antenatal care.

ocular

(ock-you-luh)

Relating to the eye.

od

Abbreviation of a Latin term meaning every day.

oedema

(uh-dee-muh)

Accumulation of fluid below the skin or in the cavities of the body.

oesophagus

(uh-sof-fa-guss)

The tube leading from the throat to the stomach.

OI

Opportunistic infection.

om

Abbreviation of a Latin term meaning every morning.

on

Abbreviation of a Latin term meaning every night.

open-label

A clinical trial where both the researcher and participants know who is taking the experimental treatment.

opportunistic infection

(opp-uh-chew-nis-tick in-feck-shun)

Specific infections which cause disease in someone with a damaged immune system.