The Collaborative International Dictionary
Jam weld
Jam \Jam\, n. [Prob. fr. jam, v.; but cf. also Ar. jamad ice, jelly, j[=a]mid congealed, jamd congelation, ice.] A preserve of fruit boiled with sugar and water; also called jelly; as, raspberry jam; currant jam; grape jam.
Jam nut. See Check nut, under Check.
Jam weld (Forging), a butt weld. See under Butt.