L*a*b*
From The Glossary of Digital Photography
A unique abbreviation of a color space. Specifically, it refers to the color space CIE 1977 L*a*b*, or CIE LAB. See CIE LAB

ONLINE GLOSSARY OF DIGITAL PHOTOGRAPY
A unique abbreviation of a color space. Specifically, it refers to the color space CIE 1977 L*a*b*, or CIE LAB. See CIE LAB