hielo

"Hielo" refers to water in its solid, frozen state, known as ice. The mental image is of clear, cold, crystalline cubes clinking against the side of a glass or the glistening frost covering a landscape on a winter morning. In everyday conversation, it is used literally when talking about beverages or weather. Figuratively, it can describe a person's cold personality or the tension in a social situation, often used in the phrase "romper el hielo" (to break the ice).
In conversation
Ordering a drink
¿Me das un refresco con mucho hielo, por favor?
Could I have a soda with lots of ice, please?
Claro, aquí tienes. ¿Quieres una rodaja de limón también?
Sure, here you go. Do you want a lemon slice too?
'Con mucho hielo' is a standard way to request a chilled drink.
Breaking the silence
Es un poco incómodo aquí, ¿verdad?
It's a bit awkward here, isn't it?
Sí, alguien tiene que romper el hielo.
Yes, someone has to break the ice.
'Romper el hielo' is a common idiom for starting a conversation in an awkward setting.
Examples
Necesito hielo para la nevera.
I need ice for the cooler.
Las calles están cubiertas de hielo.
The streets are covered in ice.
Se me quedó el café sobre la mesa y ahora parece hielo.
My coffee was left on the table and now it's like ice.