Definition of mersalyl in US English:

mersalyl

noun

Pharmacology
  • The sodium salt of a mercury-containing derivative of salicylamide, formerly used (often in combination with theophylline) to treat oedema, owing to its powerful diuretic properties; C₁₃H₁₆HgNNaO₆.

Origin

1930s; earliest use found in British Pharmacopoeia 1932. From mer- + sal- + -yl.