Glidah is the modern Hebrew word for ice- cream. I always thought it was somehow related to the Italian gelato. It turns out that this was a misconception. Avshalom Kors radio programme on the Hebrew language informed me that glidah is from the identical ancient Aramaic word meaning ice.
The Torah describes the manna that fell in the desert as having been fine and flaky, like frost on the ground (Exodus 16:14). The Aramaic translation of Onkelos renders the word for frost as glidah.
The modern word was coined by Eliezer Ben Yehuda, the reviver of the Hebrew language. This was one of his more successful neologisms. It had deep roots in Jewish sources and made sense to people that ice-cream should be called by the same name as manna, the yummiest food ever!
Glidah is also part of an inane, though rather useful, Hebrew phrase that has no English equivalent, pam shlishit glidah, meaning literally third time, ice cream. This is how its used: say youre out shopping and meet a vague acquaintance. You chat briefly and say goodbye. Ten minutes later, you run into them again. The appropriate greeting then is paam shlishit glidah, Third time, you get an ice cream. This neatly covers the awkwardness of having nothing further to say after you used up your stock of small-talk.