The term 'tm' likely refers to "trademark" in an informal or shorthand context. A trademark is a recognizable sign, design, or expression that distinguishes products or services of one entity from those of others. Trademark law helps protect brand identity and ensures that consumers can identify the source of goods or services.
The word "trademark" is derived from the combination of "trade," which comes from Old English "trade," meaning "track, course, path," and "mark," from Old Norse "merki," meaning "sign or symbol." The term has been used in legal contexts since the late 19th century.