Phytohormones, also known as plant hormones, are naturally occurring compounds that regulate various physiological and biochemical processes in plants. They play a crucial role in growth, development, and response to external stimuli. Some common synonyms for the term phytohormone include plant hormone, growth regulator, plant growth substance, and phytoactive compound. Other terms that are sometimes used to refer to these compounds include auxin, cytokinin, gibberellin, abscisic acid, and ethylene. Each of these compounds has specific functions and plays a crucial role in various stages of plant growth and development. By understanding the synonyms for the term phytohormone, scientists and researchers can better understand the various mechanisms that regulate plant growth.