This is the 8846th most frequent Swedish word.
cykelhjälm
Bicycle helmet.
Here, 'cykelhjälm' is a concrete noun referring to an item.
Jag köpte en ny cykelhjälm idag.
I bought a new bicycle helmet today.
In this sentence, 'cykelhjälm' is possessed by the speaker and is described by its appearance and comfort.
Min cykelhjälm är blå och sitter bekvämt.
My bicycle helmet is blue and fits comfortably.
This use of 'cykelhjälm' points out ownership and the location of the item.