lumberyoudaoicibaDictYouDict[lumber 词源字典]
lumber: [14] Swedish has a dialectal verb loma ‘move heavily’, which is the only clue we have to the antecedents of the otherwise mysterious English verb lumber. The noun, too, which first appears in the 16th century, is difficult to account for. In the absence of any other convincing candidates, it is presumed to have been derived from the verb (its earliest recorded sense is ‘useless or inconvenient articles’, plausibly close to the verb; ‘cut timber’ did not emerge until the 17th century, in North America).
[lumber etymology, lumber origin, 英语词源]
lumber (n.)youdaoicibaDictYouDict
"timber sawn into rough planks," 1660s, American English (Massachusetts), earlier "disused bit of furniture; heavy, useless objects" (1550s), probably from lumber (v.), perhaps influenced by Lombard, from the Italian immigrants famous as pawnbrokers and money-lenders in England (see Lombard). Lumbar, Lumbard were old alternative forms of Lombard in English. The evolution of sense then would be because a lumber-house ("pawn shop") naturally accumulates odds and ends of furniture.
Live Lumber, soldiers or passengers on board a ship are so called by the sailors. [Grose, "Dictionary of the Vulgar Tongue," 1785]


LUMBER HOUSE. A house appropriated by thieves for the reception of their stolen property. ["Dictionary of Buckish Slang, University Wit, and Pickpocket Eloquence," London, 1811]
lumber (v.)youdaoicibaDictYouDict
"to move clumsily," c. 1300, lomere, probably from a Scandinavian source (compare dialectal Swedish loma "move slowly, walk heavily," Old Norse lami "lame"), ultimately cognate with lame (adj.). Related: Lumbered; lumbering.