hair or hairs
In English hair can be singular or plural. The plural and singular form with an article can refer to one or more individual hairs.
- I found three grey hairs this morning.
- Waiter there's a hair in my soup. No wait, there are two hairs.
When referring to hair in a more generally for example, all of the hair on your head, body hair or animal hair. Then the singular form is used.
- Robert died his hair black.
- There is a lot of dog hair on the couch.
- I brush my hair everymorning.