Quick answer
"In here" is a phrase which is often translated as "aquí dentro", and "herein" is an adverb which is often translated as "aquí". Learn more about the difference between "in here" and "herein" below.
in here(
ihn
hir
)A phrase is a group of words commonly used together (e.g once upon a time).
phrase
1. (general)
a. aquí dentro
We keep the potatoes in here because it's dark and cool.Guardamos las papas aquí dentro porque está oscuro y fresco.
b. aquí
You can wait in here until your son's hearing test is done.Puede esperar aquí hasta que termine el examen auditivo de su hijo.
herein(
hir
-
ihn
)An adverb is a word that describes a verb, an adjective, or other adverbs (e.g. to run quickly, very tired).
1. (in this text)
A word or phrase used to refer to the second person formal “usted” by their conjugation or implied context (e.g. usted).
(formal)
a. aquí
The categories applied herein are defined in Annex II.Las categorías que aquí se aplican se definen en el Anexo II.
2. (in this fact or circumstance)
A word or phrase used to refer to the second person formal “usted” by their conjugation or implied context (e.g. usted).
(formal)
a. en esto
We do not have sufficient resources to complete the project, and herein lies the problem.No tenemos suficientes recursos para completar el proyecto, y en esto radica el problema.