Braided Hair, Hair Braid, Plaited Hair, Plait
noun
編む is "to knit." When you knit in threes, you are knitting in a braid style. What do you braid? Hair. That makes this braided hair.
みつあみ
The reading is the み from 三つ and つ and 編む combined into one (or should I say three?) braids. Just watch out because this isn't みっつあみ, it's just みつあみ. Listen to the audio a few times to make sure you remember how it's spelled and pronounced!
おいおい、頼むよ。明らかにお前たちの相性全然よくなかっただろ！絶対にあの三つ編みの女に電話なんてしない方がいいって！
Oh come on, it was so obvious! There was no chemistry between you two! You definitely shouldn’t call that girl with the braided hair!