Weld
late 16th century (in the sense ‘become united’): alteration (probably influenced by the past participle) of well2 in the obsolete sense ‘melt or weld heated metal’.
wiktionary
From Middle English welde, wolde, from Old English *weald, weard, variant from of wād, Proto-West Germanic *waiʀd, from Proto-Germanic *waizdaz. Alternatively reborrowed from or contaminated by Anglo-Norman wold, wolde (compare Old French guaide). Doublet of woad. [1]
Alteration of well(“boil, rise”), probably influenced by the past participle, welled.
From Old English weald (sense 2).
etymonline
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.
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.).
