What does the suffix -oid signify in medical terminology?

The suffix -oid in medical terminology signifies "resembling" or "like." This means that when a term ends with -oid, it often describes something that has characteristics similar to something else. For instance, "cytoid" refers to something resembling a cell, and "adenoid" refers to gland-like tissue that resembles lympoid tissue.

In terms of the other options, a suffix indicating "malignant tumor" would typically be “-sarcoma,” signifying a type of cancer, while "abnormal condition" is often noted with the suffix “-osis.” The suffix indicating "condition of formation" is usually represented by “-genesis” or “-plasia.” Thus, the choice that aligns with the definition of "-oid" as "resembling" is the correct one.