Meaning of L- in English

L-

[l-] prefix [ISV, fr. lev-] 1: levorotatory "l-tartaric acid"

2: having a similar configuration at a selected carbon atom to the configuration of levorotatory glyceraldehyde--usu. printed as a small capital "l-fructose"

Merriam-Webster English vocab.      Английский словарь Merriam Webster.