This is a picture of my sofa. There is a tight space between the arm and the seat of the sofa.
If you have a cover, you can tuck the cover in this tight gap.
Is that tight space called a gap?
For example, there is a toy stuck in the gap in the sofa.
But "a gap" has quite a big space.
I did my research and it seems to be called "crevice". But I want a common word that is used in everyday English.
What is a tight narrow space between things that are in tight contact with each other called in everyday English?