LD may refer to any of the following:
Sometimes abbreviated as LD, a laserdisc is an 8" to 12" wide disc that holds full-length video and audio recordings. Today, laserdiscs are no longer in use. They were succeeded by DVD and Blu-ray.
Linux command, see the ld command page for additional information on this command.
LD is also chat slang for Long distance.
Chat slang, Computer abbreviations, Laser