Coretta is an English elaboration of Cora, from the Greek korē (maiden). Coretta Scott King (1927-2006) — wife of Martin Luther King Jr. and civil rights leader in her own right who continued her husband's work after his 1968 assassination. Founded the Martin Luther King, Jr. Center for Nonviolent Social Change in Atlanta (1968); led the successful 15-year campaign to establish Martin Luther King Jr. Day as a US federal holiday (signed into law 1983); spoke out early against apartheid, the Vietnam War, and LGBTQ discrimination.
Subject of Octavia Vivian's Coretta: The Story of Coretta Scott King (2006).
Coretta 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 Coretta reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.