What part of speech is the first word in a scientific name?

A prefix.

Examples:

Bio-logy: The prefix bio means life, and the suffix ology means the study/field of. Combined they give the meaning; the study of life.

Hydro-philic: The prefix hydro means water, and the suffix philic means the love of. Combined the give the meaning; water loving.

Astro-logy: The prefix astro means star, and the suffix ology means the study/field of. Combined they give the meaning; the study of stars.

answer; ///i believe its: ///(embolus);

i thinking chemical change