I. sol ‧ der 1 /ˈsɒldə, ˈsəʊl- $ ˈsɑːdər/ BrE AmE noun [uncountable]
[ Date: 1300-1400 ; Language: Old French ; Origin: soudure , from souder 'to solder' , from Latin solidare 'to make solid' , from solidus ; ⇨ ↑ solid 1 ]
a soft metal, usually a mixture of ↑ lead and ↑ tin , which can be melted and used to join two metal surfaces, wires etc
II. solder 2 BrE AmE verb [transitive + onto/together]
to join or repair metal surfaces with solder