early 19c., of writing, from holograph + -y (4); physics sense, "process of using holograms," is from 1964, coined by discoverer, Hungarian-born physicist Gábor Dénes, from hologram on analogy of telegraphy/telegram.
"document written entirely by the person from whom it proceeds," 1620s, from Late Latin holographus, from Greek holographos "written entirely by the same hand," literally "written in full," from holos "whole" (from PIE root *sol- "whole, well-kept") + graphos "written," from graphein "to write" (see -graphy). Modern use, with reference to holograms, is a 1960s back-formation from holography.
suffix indicating state, condition, or quality; also activity or the result of it (as in victory, history, etc.), via Anglo-French and Old French -é, from Latin -ia, Greek -ia, from PIE *-a-, suffix forming abstract or collective nouns. It is etymologically identical with -ia and the second element in -cy, -ery, -logy, etc.