QUICK ANSWER
"Hola" is a form of "hola", an interjection which is often translated as "hello". "Buenas noches" is a form of "buenas noches", a phrase which is often translated as "good evening". Learn more about the difference between "hola" and "buenas noches" below.
hola
An interjection is a short utterance that expresses emotion, hesitation, or protest (e.g., Wow!).
1. (general)
b. hi (colloquial)
A word or phrase that is commonly used in conversational speech (e.g., skinny, grandma).
¡Hola! ¿Qué hay de nuevo?Hi! What's new?
buenas noches(
bweh
-
nahs
noh
-
chehs
)A phrase is a group of words commonly used together (e.g., once upon a time).
1. (salutation)
2. (farewell)