"Attomolar" is a scientific term used to describe a concentration of a substance that is extremely low - one attomole per liter. There are several synonyms for the word "attomolar" that can be used in scientific research, including "zeptomolar" (one thousandth of an attomole), "yoctomolar" (one septillionth of a mole), and "femtomolar" (one quadrillionth of a mole). These synonyms are used to describe even lower concentrations than attomolar and are incredibly important in fields like chemistry and biology. Researchers rely on accurate measurements of these concentrations to better understand the behavior of biomolecules and other microscopic particles.