OXFORD DICTIONARY
Re, abbr.
1 (in the UK) Royal Engineers.
2 religious education.
Re, symb. Chem. the element rhenium.
Re, prep.
1 in the matter of (as the first word in a heading, esp. of a legal document).
2 colloq. about, concerning.
THESAURUS
Re
about, anent, apropos of, as, as for, as regards, as respects, as to, concerning, in connection with, in point of, in re, in reference to, in regard to, in relation to, in relation with, in respect to, of, on, pertaining to, pertinent to, referring to, regarding, relating to, relative to, respecting, speaking of, touching, upon, with regard to, with respect to