It is a decoding skill, not a vocabulary list
Medical terms are built from a small set of roots, prefixes, and suffixes that recombine predictably. Someone who has memorised two thousand terms knows two thousand terms; someone who has learned the parts can decode a term they have never seen. That difference is what the practice test is built to measure, which is why so many questions give an unfamiliar word and ask what it must mean.
Where the certification actually sits
Terminology is rarely certified by itself. It appears as a component of role-specific credentials — clinical medical assistant, billing and coding, patient care technician — issued by bodies such as NHA or AAPC. Choose the role first and the certification follows from it; learning the terminology is preparation for whichever you pick rather than a destination.
Why precision matters more here
Hypertension and hypotension differ by two letters and mean opposite things. Proximal and distal, anterior and posterior, -ectomy and -ostomy are the same kind of pair. In most fields a near-miss on a word is a communication problem; in this one it can be a patient-safety problem, which is why the discipline of decoding carefully is the actual skill being taught.