
Curtis S. answered 03/14/19
HS/College/Adult Spanish tutor with 50 years' speaking Spanish
The Spanish word azúcar means "sugar." It is invariably masculine. If you have seen it with the feminine "la," it was likely in the context of a girlfriend referred to as "sweetie," although I have never seen that.
There are words where both versions articles can be used, though. Examples would be the plurals of el águila and el aqua. Both are feminine, but take the masculine el in the singular form. They become las águilas and la agues in the plural. Likewise, some professions like accountant (countable) could take both forms, depending on whether the person is a male or female.
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