soda, lye, sodium hydroxide (NaOH) / sodium (Na) / sodium carbonate (Na₂CO₃) / seepweed, sea blite, saltwort (plants, usually of the genus Suaeda, which produce sodium carbonate when burned) / prickly saltwort (Salsola kali, syn. Kali turgidum)

caustic soda, lye

baking soda, sodium bicarbonate

blowtorch

to solder

welder

welding machine

third-person singular conditional of souder

third-person plural conditional of souder

plural of soudeur