This is the 100th most frequent Hebrew word.
בתוך
"Inside" or "within."
'בתוך' is used here to indicate physical containment within an object.
הספר נמצא בתוך התיק.
The book is inside the bag.
'בתוך' is used here to express an occurrence within a time frame.
הוא נרדם בתוך עשר דקות.
He fell asleep within ten minutes.
'בתוך' is used here metaphorically to describe an inner, emotional state.