Combination of Linda or Lyn ('beautiful, soft') with the suffix -dell ('valley').
Lyndell is an American elaboration of the Old English place-name element *lind* (lime tree or linden tree) combined with *dell* (a small wooded valley), yielding the pastoral meaning "valley of the linden trees." The linden — known in North America as the basswood — was among the most culturally significant trees of northern Europe, associated with justice (village assemblies were often held beneath lindens), love (in German folk tradition), and healing. Names rooted in *lind* include Linda, Lindsay, and Lyndon, giving Lyndell a large and varied family.
The -dell suffix places the name firmly in an American vernacular naming tradition that flourished in the early and mid-twentieth century, when parents created melodic, distinctly New World names by combining familiar sounds in novel ways. Names like Randell, Wendell, and Cordell follow the same pattern, suggesting both English pastoral roots and a confident American originality. Lyndell was most frequently given in the American South and Midwest during the 1940s through 1960s, where it carries associations of a particular mid-century graciousness.
Lyndell is rare enough today that most bearers of the name will go their entire lives without meeting another — a quality that some find isolating and others find liberating. It has an appealing visual balance on the page and a soft, unhurried sound. Its connections to nature (trees, valleys), to the broader Linda/Lynn family of names, and to distinctly American naming creativity make it a name of quiet, genuine character. It is the kind of name that sounds both invented and inevitable.