1, different parts of speech and meanings:

Near preposition, in, near.

Almost, adverb, almost, almost.

Nearby, adjective, nearby.

2. Different usage:

Near means near, which is a preposition used in front of nouns, such as near the window.

Jin is an adverb, indicating almost, indicating degree and modifying adjectives. For example, it's almost two o'clock.

Nearby is often used as an adjective. Used as a pre-attributive or post-attributive, indicating nearby, nearby, nearby.

3, the scope of use is different:

When describing "near", near and near both mean near, meaning "close in space". Near has a broader meaning, which also means "close in time and degree". Neary as an adverb means almost, almost, almost, and as an adjective means close.