Macrina (Μακρίνα) is from the Greek makros (long, great). Saint Macrina the Younger (c. 330-379) was the Cappadocian Christian philosopher and elder sister of Basil the Great and Gregory of Nyssa — the family that shaped Greek-Orthodox theology.
Called "the teacher" (didaskalos) by her brothers.
Macrina 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 Macrina reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.