What does "fluid drachm" mean?

A British unit of volume equal to 60 minims or 3.55 ml.

What is a synonym for "fluid drachm"?

Common synonyms include: drachm, fluid dram, fluidram.

noun

noun ·Rare ·Advanced level

Noun

1
A British unit of volume equal to 60 minims or 3.55 ml.
2
a unit of capacity or volume in the apothecary system equal to one eighth of a fluid ounce wordnet
3
a British imperial capacity measure (liquid or dry) equal to 60 minims or 3.5516 cubic centimeters wordnet

From Ancient Greek δραχμή (drakhmḗ, “a weight and coin”).