From lechem; foodful; Lachmi, an Israelite; or rather probably a brief form (or perhaps erroneous transcription) for Beyth hal-Lachmiy -- Lahmi. See also Yashubiy Lechem.
KJV: And there was war again with the Philistines; and Elhanan the son of Jair slew Lahmi the brother of Goliath the Gittite, whose spear staff was like a weaver's beam.
NASB: And there was war with the Philistines again, and Elhanan the son of Jair killed Lahmi the brother of Goliath the Gittite, the shaft of whose spear was like a weaver's beam.