ARCHIVED: This Practice Note has been archived and is not maintained. This Practice Note was originally written for Lexis Practice Advisor®, in the US. This Practice Note provides an overview of key trademark law principles, including the requirements for trademark protection, ownership, proper trademark usage, the ways in which trademark rights may be lost (eg through abandonment, genericide, naked licensing, or assignments in gross), limitations on trademark protection (eg the first-sale doctrine, descriptive and nominative fair use, laches, acquiescence), enforcement, and remedies. What is a trademark? Trademarks are typically words, phrases, symbols, and/or designs that are used as source identifiers for particular products. Service marks are the same as trademarks, except that they are used as source identifiers for particular services. However, both trademarks and service marks are commonly referred to simply as ‘trademarks’ or ‘marks’. Under the ‘Information matter’ doctrine, a mark cannot be registered if, rather than identifying the source of a product or service, the mark merely conveys informational matter, see In re Go & Assocs, LLC, 90 F.4th 1354, 1357 (Fed. Cir. 2024)