In both winter and monsoon months, níyol is often accompanied by k’os, which is the Navajo word for cloud.
In common usage, the word daak’os is also used to refer to a multitude of clouds.
There is also the word ak’os which is the non-possessive word for “neck,” i.e. “a neck.”
The body part needs shi-, ni-, bi-, etc. to form shik’os (sik’os), nikos, bik’os, etc. to differentiate it from the word for cloud.
So k’os and ak’os are separate terms.