안 (an) · 속 (sok) · 내부 (nae-bu, naebu)
'안' is casual and general inside, '속' implies inner parts or contents, and '내부' is formal, often for structures or organizations.
One lane per word — no nested boxes, just the gist.
The most common and general word for 'inside,' mainly used in everyday conversation.
When to use
casual speech, inside places, simple location
The nuance
Used in casual speech to indicate the inside of a place or space, without focusing on structure or contents.
'Sok' refers to the inner part or contents contrasting with the outside, often abstract or physical contents.
When to use
contents expression, human emotions, essence description
The nuance
Used to express inner contents or essence of things, or emotions inside a person, focusing on content rather than physical space.
A formal and written term for the interior of buildings, organizations, or systems, emphasizing structure.
When to use
formal documents, building structure, organization description
The nuance
Used in documents, reports, or formal contexts to describe structural or organizational interiors, not casual speech.
방 안에 책이 있어요.
bang an-e chaek-i iss-eo-yo., bang an e chaek i iss eo yo.
'안' is appropriate for casual inside a place.
방 속에 책이 있어요.
bang sok-e chaek-i iss-eo-yo., bang sok e chaek i iss eo yo.
'속' is for contents or essence, not physical space.
건물 내부가 깨끗합니다.
geon-mul nae-bu-ga kkae-kkeus-hap-ni-da., geon mul nae bu ga kkae kkeus hap ni da.
'내부' fits formal structural interior description.
건물 안이 깨끗합니다.
geon-mul an-i kkae-kkeus-hap-ni-da., geon mul an i kkae kkeus hap ni da.
'안' can be used casually for building interiors.
사과 안이 맛있어요.
sa-gwa an-i mas-iss-eo-yo., sa gwa an i mas iss eo yo.
'안' is not suitable for contents inside fruits.
사과 속이 맛있어요.
sa-gwa sok-i mas-iss-eo-yo., sa gwa sok i mas iss eo yo.
'속' correctly expresses inner contents of food.
그 사람 마음 안이 복잡해요.
geu sa-ram ma-eum an-i bok-jap-hae-yo., geu sa ram ma eum an i bok jap hae yo.
'안' is unnatural for emotions; use '속'.
그 사람 마음 속이 복잡해요.
geu sa-ram ma-eum sok-i bok-jap-hae-yo., geu sa ram ma eum sok i bok jap hae yo.
'속' is used for inner emotions or mind.
Which word best expresses the inside of fruit?
Which word suits describing a building's structural interior in a formal report?
Which word is mainly used in casual speech to talk about inside a place?
What does it mean?
