How to read the band →
Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Gwendolyn
Gwendolyn is now well below its former popularity. All-time it's been given to 124,718 U.S. babies, the 774th most common name by sound today, peaking at 3,531 in 1953, with 848 in 2025.
Gwendolyn has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).