Hormone

Definition

Hormone is a noun referring to a signaling molecule produced by endocrine glands and transported in the bloodstream to target organs, where it regulates physiology and behavior. Its plural form is hormones.

Parts of Speech

• Noun

Pronunciation

American English

• IPA: /ˈhɔr.moʊn/
• Respelling: HOR-mohn

British English

• IPA: /ˈhɔː.məʊn/
• Respelling: HOR-mohn

Etymology

Late 19th century: from Greek hormōn “impetus, setting in motion,” from hormaein “to set in motion.”

Derivatives

• hormonal (adjective)
• hormonally (adverb)
• hormone-like (adjective)
• hormonogenesis (noun)
• hormone therapy (noun)
• hormone receptor (noun)

Synonyms

• endocrine factor
• chemical messenger
• messenger molecule

Antonyms

• None

Usage

The noun "hormone" is used in medical, biological, and physiological contexts to refer to chemical messengers secreted by glands. For example, "Insulin is a key hormone regulating blood sugar," or "Stress hormones like cortisol prepare the body to respond to danger."

Related Terms

• Endocrine gland: An organ that secretes hormones directly into the bloodstream.
• Receptor: A protein on a cell that binds a specific hormone.
• Endocrine system: The network of glands that produce and release hormones.
• Homeostasis: The maintenance of stable internal conditions by hormonal regulation.
• Signal transduction: The process by which a hormone’s binding triggers cellular responses.

Detailed Definitions

Noun

• A chemical messenger secreted by endocrine glands into the bloodstream – regulates growth, metabolism, reproduction, mood, and other physiological processes.
  • Example: "Thyroid hormones control metabolic rate."
• Any signaling molecule acting in low concentration at a distant target site – includes peptides, steroids, and amino acid derivatives.
  • Example: "Plant hormones like auxin influence stem elongation."