複数の細胞が直接または間接的に情報や刺激をやり取りし合う現象を指す。これは、発生、組織形成、恒常性の維持、免疫応答、疾患進行など、あらゆる生理・病理現象に不可欠である。細胞は物理的な接触、分泌因子（サイトカイン、成長因子など）、細胞外マトリックスを介して互いに影響を与え合う。

This term refers to the phenomenon in which multiple cells exchange information and signals, either directly or indirectly. It is essential for all physiological and pathological processes, including development, tissue formation, maintenance of homeostasis, immune responses, and disease progression. Cells influence one another through physical contact, secreted factors (such as cytokines and growth factors), and the extracellular matrix.