Avery is an English surname turned given name — from the Old French Auvery, itself from the Old Germanic Alberic, meaning "elf ruler" or "wise counsel." The same root that gives Aubrey, Albert, and the medieval king of the dwarves Alberic.
Avery is unisex but used overwhelmingly for girls in the U.S. since the 2000s. It entered the top 100 in 2003 and now sits in the top 30 — a modern surname-name with mythic Germanic roots.
Avery reduces to four — the number of steadiness and quiet competence.