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).
Trinity
Trinity is now well below its former popularity. All-time it's been given to 88,192 U.S. babies, the 737th most common name by sound today, peaking at 5,729 in 2004, with 734 in 2025.
Trinity has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).