messenger

A messenger is an individual, device, or system that conveys information from one party to another. The term spans many domains, describing human couriers, postal and logistics services, and technologies that transmit messages electronically or symbolically.

Historically, messengers included runners, horse riders, and heralds who carried letters, orders, or proclamations. In empires and militaries, messengers maintained line-of-sight communication and relayed requests across long distances.

In contemporary use, messenger often refers to electronic messaging systems. These include email, SMS, and instant messaging apps that exchange text, voice, images, and files. Modern platforms support real-time and asynchronous communication, group chats, and privacy features such as encryption in transit or at rest.

In biology and physiology, messengers are molecules that convey signals between cells or organs. Messenger RNA (mRNA) carries genetic information from DNA to ribosomes for protein synthesis. Hormones, neurotransmitters, and other signaling molecules act as chemical messengers coordinating bodily functions.

In branding and culture, the term appears in product names and services, such as messaging apps and courier services. The concept of a messenger also extends to logistics, where dedicated couriers deliver letters, packages, or digital messages to recipients.