Which medical terminology root indicates the presence of a clot?

The root "thromb/o" specifically refers to a clot, particularly in the context of blood. This term is derived from the Greek word "thrombos," which means clot or lump. It is commonly used in medical terminology relating to conditions such as thrombosis, which is the formation of a blood clot in a blood vessel, leading to various health issues.

Focusing on the other options helps clarify their meaning: "bacteri/o" pertains to bacteria and is involved in terms related to infections or bacterial presence. "poikil/o" signifies variations or irregularities, often used in describing red blood cell shapes in conditions like poikilocytosis. "erythr/o" is associated with red blood cells, relating to conditions such as erythrocytosis, which involves an increased number of red blood cells. None of these terms relate to clots, which reaffirms why "thromb/o" is the correct choice in this context.