Euchromatin is a term used to describe chromatin that is less compact and more accessible to the transcriptional machinery than its counterpart, heterochromatin. There are a few synonyms for the word euchromatin, including open chromatin, active chromatin, and gene-rich chromatin. These terms are interchangeable and all refer to chromatin regions that are less condensed and therefore permit access to transcription factors, enabling gene expression. Additionally, euchromatic regions are more likely to undergo epigenetic modifications such as histone acetylation or methylation. Understanding the terminology related to chromatin structure is crucial for understanding how genes are regulated and expressed.