Longman Dictionary of Contemporary English
Wiktionary
n. sugar shaped in cubes (or approximate cubes), often used for coffee or tea
Usage examples of "sugar cube".
She grabbed her mug and filled it with coffee, adding a sugar cube, and took a look at the weather and ferals report before going to get dressed.
He daintily took a sugar cube from the bowl on the tray and rubbed it between his palms.
My father put a sugar cube into his coffee and stirred it, and tapped the spoon on the side of the cup.
He pulled out a sugar cube and held it up, and grinned through the C of his thumb and finger.
Max dropped a sugar cube onto his tongue and took some time sucking the goodness out of it.
In any case, it was taken in a similar way, injected into a sugar cube and then the sugar cube sucked and swallowed.
Sucking on his sugar cube, a rare treat given the price of sugar, he kept his face buried in Lora's shoulder through the whole operation.