Jenna is an English-American invention from the 1970s — possibly a respelling of Jenny + the Italian -a feminine ending, or a contraction of Jennifer (Welsh Gwenhwyfar, "white phantom"). Bush; Today show co-anchor. Jenna Coleman — Doctor Who (2012-2015), Victoria (2016-2019). Jenna Jameson — adult-industry pioneer.
Jenna does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Jenna reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.