Some context might be helpful, but...
I would refer to "a single strand of hair."
I might say, "I like her hair," referring to the hair on her head. In this case, I mean all the hair on her head.
"Hairs" is something I don't know I would ever say. I suppose you could say "I found three hairs" in my food. In this case, we use "hairs" as the plural of individuals, if that makes sense.
I hope this helps.
vincentAugust 2019Thanks Tace
I want to comment on whether "hair" is a countable noun.
After reading the responses, I see that "hair" can refer to a noun that is countable, OR a noun that is not countable, depending on context.
You can say, "He doesn't have much hair." The word "much" describes an uncountable amount. If your intention is to name an exact number of hairs for whatever reason, you can say, "I found a hair in my food," or "I found three hairs...."
You could also refer to it in an uncountable way. "She has a lot of hair," or "...beautiful hair."
I know we have beaten this horse to death, but if you get anything out of it, it is worth it. If you don't get anything out of it, there is still no harm done; and you are too smart to be confused.
Something I made note of a while back, so I thought I may as well add since it’s come up now, sure, we use ”hair” to mean ” a person’s hairstyle”, however, when I was playing this avatar chat game, where you can change your outfits, of course player ended up saying ”different hairs” of course what they really meant was ”different hairstyles”. I hope this is helpful. Also we have the expression ”to split hairs” - means to go off talking about something irrelevant to the matter at hand.
Did you know that "hair" is an uncountable noun. That's why we say 3 strands of hair and not "3 hairs"
AussieInBgJune 2021A strand of hair is actually a bundle of the substance ”hair” twisted together to form a single length/piece.
This is why ”hair” is uncountable here.
It’s possible to use ”strand” + ”hair” when ”hair” is a countable noun, e.g.
”a strand of a few hairs”
but this is relatively rare.
vincentAugust 2019Thanks Jaafar