What does ice mean on Apple?

Could you please clarify what the term "ice" refers to in the context of Apple? I'm curious to know if it's related to a specific feature, service, or terminology used by the company. Is it perhaps a slang term or nickname for something official? Or does it have a different meaning entirely? I'm quite interested in understanding this better, and I'm sure many others would be as well. Could you provide some insight into this matter? Thank you in advance for your assistance.