d, l, dl [obsolete]
Obsolete (usage strongly discouraged) alternatives for, respectively, the prefixes (+)- and (−)- [used to designate the sign of optical rotation of enantiomers under specified condition (and hence to distinguish the enantiomers)] and (±)- for a racemate.
Source:
PAC, 1996, 68, 2193 (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2205