noun

1. 1. sodium oxide, NaO
   2. sodium bicarbonate
   3. sodium carbonate
   4. sodium hydroxide
2. 1. soda water
   2. ☆ soda pop
   3. ☆ a confection of soda water flavored with syrup, fruit, etc. and served with ice cream in it
3. ☆ in faro, the card turned up in the dealing box before play starts

Etymology: ML (or It or Sp) < Ar suwayd, burnt plant (from which soda was produced), dim. of ʾaswad, black