Eosin is a synthetic dye commonly used in histology and microscopy to stain biological tissues. It is particularly effective in highlighting cell structures, making it easier to observe under a microscope. Eosin binds to proteins, giving tissues a pink or red color, which contrasts well with other stains, such as hematoxylin, that stain nuclei blue. This dye is often used in combination with hematoxylin in the H&E staining technique, a standard method for examining tissue samples. Eosin's ability to differentiate between various cellular components aids pathologists in diagnosing diseases and studying tissue morphology.