weld (n.1)

plant (Resedo luteola) producing yellow dye, late 14c., from Old English *wealde, perhaps a variant of Old English wald "forest" (see wold). Spanish gualda, French gaude are Germanic loan-words.

weld (n.2)

"joint formed by welding," 1831, from weld (v.).

weld (v.)

1590s, "unite or consolidate by hammering or compression, often after softening by heating," alteration of well (v.) "to boil, rise;" influenced by past participle form welled. Related: Welded; welding.