동안(dong-an, dongan)
Denotes the entire duration of a specific time period
When to use
Action duration, State maintenance period, Entire time span
The nuance
Used after verbs or adjectives to emphasize the duration of an action or state, referring to the whole period from start to finish.
사이(sa-i, sai)
Indicates the relationship or interval between two objects or points in time
When to use
Interval between two objects, Interval between two time points, Relationship between people
The nuance
Placed between two nouns to indicate spatial or temporal interval or relationship; emphasizes distance or period between two points.
가운데(ga-un-de, gaunde)
Indicates the center or middle position among multiple objects
When to use
Spatial center position, Temporal midpoint, Middle among multiple objects
The nuance
Used to indicate the central position among multiple nouns; can be spatial or temporal midpoint but mainly emphasizes the center.