A soothing tombstone for your throat

Faithful Wordlady readers will know that I sing in a choir. At least, I do when not being asphyxiated by incense or rendered mute by some nasty laryngitis-inflicting virus. With this being Holy Week, it's a major singathon for church choristers, and, not surprisingly, there's usually a stash of throat lozenges somewhere in the choir room. But why are these soothing candies called that?
A lozenge was originally a diamond-shaped figure in heraldry.




Since heraldry was a preoccupation of the French-speaking aristocracy rather than of the Anglo-Saxon lower classes in medieval England, this is yet another word that we acquired from French.
There are two theories as to where the French got it. It may have come from a Provençal word lausa derived from Latin lapis (stone). In some Romance languages this derivative meant "roofing slate" or "slab" or, more ominously considering what lozenges are used for today, "tombstone".  A second possibility is that it goes back to a word in Pahlavi  (a Persian language), lawz (almond), because an almond is shaped like a diamond.
The reason we now use the word for a type of cough drop is that in the 1500s, medicated pills were made in a diamond shape. Eventually, the idea of the medication it contained became more important than the shape of the pill, so now we have round lozenges as well as quadrilateral ones.
For the origin of the word "Easter", please see this post.