Why does “glaciaĵo” mean “ice cream”?

Question

Given the meaning of the suffix "-aĵ", that is, "a concrete thing", and the examples usually associated with it, like (random ones from PMEG):

utila → utilaĵo = (konkreta) afero, kiu estas utila

dolĉa → dolĉaĵo = io karakterizata de dolĉa gusto (bombono k.s.)

ligno → lignaĵo = io farita el ligno

And looking at the definition of "glaciaĵo" in a later section on the same page on PMEG:

glacio → glaciaĵo = dolĉaĵo el glacieca kremo

I find the definition of „glaciaĵo“ strange because:

1. Why does it mean „ice cream“ of all the things that can be made of ice? This seems too particular, especially since ice is by itself not sweet.
2. Thinking about that, ice cream is not really made of ice. It's made of cream, milk, or even mashed bananas. Yes, it is cold as ice but it's not ice.

So, does anyone know whether this was a word/example made by Zamenhof? Or did it evolve naturally (therefore not really following strict logic)? Or did it feel logical in the time of Zamenhof (like maybe ice cream was indeed made of ice back then)?

Answer 1

As explained in PMEG, -aĵ- is often used to form words for prepared foods. The word glaciaĵo falls into this category. I always found it very logical, once one knows that -aĵ- can have the special meaning of a prepared food. Ice cream is a prepared food that is technically a kind of ice. The fact that many other languages have a word related to ice for ice cream makes it even more suitable.

You shouldn't think of the meaning of Esperanto compound words as being precisely by the meaning of its parts. Compound words exist because they are easier to memorize than separate word roots, but their precise meaning still has to be either learned or inferred from the context in which they are used.

Answer 2

I think the word formation from suffixes should be thought of as more of a tool to aid memorisation rather than a completely logical system. Often the constructed word takes on a very concrete meaning that doesn't always follow on from the more general meaning that could be interpreted from the components. Although ice cream isn't the only thing glaciajô could mean, it does have some relation to ice. I imagine the word was chosen because it is similar to the formation from other languages. For example in French I believe people just say une glace which is just literally “an ice”. In Italian the word is gelato. According to Wikitionary this is “gel(o) ‎(“frost”, “cold”) +‎ -ato ‎(past participle suffix)” which is sort of similar to the way it is formed in Esperanto.

There are other examples of constructed words that have taken on a very specific meaning. For example flugilo is specifically a wing and would not be used to refer to a jetpack, even though that is also a tool for flying.