Etymology From Middle English souder, soudere, soudur (noun), from Old French soldure, soudeure (noun), from Old French souder, solder (“to solder”, verb) (> Middle English souden (“to solder”)), from Latin solidāre (“make solid”).
1
Any of various easily melted alloys, commonly of tin and lead, that are used to mend, coat, or join metal objects, usually small.
...the packaging of electronic components has moved from technology that used solder predominantly as an electrical connection (plated through-hole) to technology that uses solder as both a mechanical and electrical connection (surface mount technology)...1991, John H. Lau, Solder Joint Reliability: Theory and Applications, Springer Science & Business Media, →ISBN, page 225:
I've had so little feeling that I've burned myself with liquid solder and watched my skin burn and not felt anything.1991 December 8, Liz Galst, quoting Buck, “Gay Male Incest Survivors, Safer Sex, and AIDS”, in Gay Community News, volume 19, number 21, page 9:
2
Figuratively Circumstances or emotions that strongly bond things or persons together, by analogy to solder that joins metals.
Friendship! Mysterious cement of the soul — and solder of society.1860, D R. M'Nab, Christian consolation; The way home; and Conjugal love:
Etymology From Middle English souder, soudere, soudur (noun), from Old French soldure, soudeure (noun), from Old French souder, solder (“to solder”, verb) (> Middle English souden (“to solder”)), from Latin solidāre (“make solid”).
1
To join items together, or to coat them with solder.
In the days that followed Nick's death I was in severe shock. I was shattered both physically and emotionally... I seemed to be living in slow motion, waiting for the fragmented parts of my body and mind to solder themselves together.2013, Elizabeth Burton-Phillips, Mum, Can You Lend Me Twenty Quid?: What drugs did to my family, Little, Brown Book Group, →ISBN, page 137?: