"Cell-free" refers to a sample or environment that is devoid of any living cells or cellular components. Synonyms for this term include "cell-deficient," "cell-extracted," "cell-removed," and "acellular." These terms are often used in scientific research to describe experimental conditions or samples that are specifically designed to study non-cellular biomolecules or pathways. Other synonymous terms include "cell-free supernatant," "cell-free extract," or "cell-free culture," indicating samples that are produced after cells are removed through centrifugation, filtration, or other methods. Understanding these synonyms is important for scientists who work with biological materials and who desire to isolate and study specific molecules and pathways without the interference of living cells.