twenty-third letter of the Greek alphabet
Ψ (psi) is the twenty-third letter of the Greek alphabet, used in writing the Greek language. It appears in English primarily through Greek-derived scientific and mathematical terms, making it a symbol readers encounter in academic and technical contexts.
AI-generated from the Wikipedia summary — may contain errors.
History
Archaic local variants
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).