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