General term for frozen sweets, including ice cream, sherbet, and popsicles.
In summer, various frozen desserts appear in stores.
かき氷 is shaved ice with syrup, a specific type of 氷菓子.
Compound of 氷 (こおり, 'ice') and 菓子 (かし, 'confectionery'). The reading こおりがし follows standard rendaku voicing of the second element.