What do you call joined letters? (ae, oe)

Factual Questions
21

To clarify on the above post, in typography, ligatures are primarily used for readability and aesthetics. The most commonly ligatured characters are “fi” “fl” “ff” “ffi” and “ffl.” The problem with unligatured letters is especially visible in large, serifed font families, especially if they’re tightly tracked (or kerned). The problem is, the overhand of the “f” bumps into the dot of the “i,” and that’s just ugly. For this reason, there’s a ligature which fuses the top of the “f” with the “i” and all looks hunky-dory.

And they are fairly common. Picking up five books at random, three of them contained ligatured "fi"s.

22

Quick question:

Is there an specific term in the French language to refer to ligatures (for instance, the œ in cœur)?

Thanks.

23

Well, my Larousse says that the French word for ligature is ligature, although I don’t know anywhere near enough rules of French grammar, syntax, or orthography to know whether they use the same term for the œ construction.