The abbreviation LM or lm may refer to:
No.5551 The Unknown Warrior is a steam locomotive which is under construction as a "new-build" project.
Lamin A/C also known as LMNA is a protein that in humans is encoded by the LMNA gene. Lamin A/C belongs to the lamin family of proteins.
The LM317 is a popular adjustable positive linear voltage regulator. It was designed by Robert C Dobkin in 1976 while he worked at National Semiconductor.