Deklan is of Irish origin, derived from the Gaelic word "Donnchadh," which means "dark haired warrior." It was popularized by American author Thomas Pynchon's 1973 novel "Gravity's Rainbow," in which he used Deklan as a character name. The name gained further popularity through its use in several TV shows and movies since the late 20th century. Deklan is composed of two elements: "Donn" meaning dark or brown, and "chad" meaning battle or war. Therefore, it can be interpreted to mean "dark warrior." It typically follows the pronunciation /DEK-luh n/. The name has been more commonly used in English-speaking countries since the mid-20th century but remains relatively uncommon compared to other names.
"Deklan experienced a significant increase in popularity over the years, with a marked jump from just 6 births in 1998 to a peak of 193 in 2018. However, it has since declined somewhat, with only 82 births recorded in 2023."