The lower-case letter φ is used as a symbol for:
The upper-case letter Φ is used as a symbol for:
See also other things named phi, Phi phenomenon.
... scientist February 1 - S. J. Perelman[?], humorist, author February 4 - MacKinlay Kantor[?], historian (+ 1977) February 5 - Walter Gross[?], cabaretist (+ 1989) ...