Learn Italian: La neve è bianca.

In Italian, when you talk about a broad category or make a general statement, you almost always need to use the definite article. So while English just says "Snow is white," Italian requires La neve è bianca.

The word neve ends in -e. How do I know it is feminine?

Nouns ending in -e can be either masculine or feminine in Italian, so you have to memorize their gender as you learn them. Because neve happens to be feminine, it takes the feminine article la.

If the dictionary says the word for white is bianco, why is it bianca here?

Adjectives must match the noun they describe. Since la neve is a feminine singular noun, the basic masculine adjective bianco changes its ending to -a to become the feminine singular bianca.