Hulu

1.  Feather, quill, plumage.  
2.  Esteemed, choice, precious.  
3.  fur, wool, fleece, human body hair. 
4.  Kind, nature, color.  
5.  Hackle; fishhook with barb on the outside.  
6.  Brush.  
7.  Muscle attaching a bivalve to rocks.  
8.  Seal.  
9.  Cloth. 

        Of all these translations the first three seem to be the most well-known and widely used so we'll concentrate on those.  Below are some explanations referring to the specific translations:

1.  Hulu refers to the feathers or plumage of birds. Hulu manu - bird feather (often "manu" follows hulu when referring to feathers to differentiate it from the fur of any animal). 
        Ka hulu 'i'iwi nani - the beautiful ʻiʻiwi bird feathers

2.  Frequently the elderly are often referred to as hulu kupuna - esteemed grandparent.  The translation of esteemed or prized might be related to the fact that bird feathers were highly prized in  Hawaiʻi and used in symbols of royalty such as capes, lei and helmets.

3.  Any human hair, with the exception of the hair on the top of our head (which is lauoho) is known as hulu or huluhulu.  Similarly, any fur on animals is also hulu.

He huluhulu kau i ka puka ihu - Hair growing inside of the nostril (said in envy of a person who is regarded as a favorite by a superior--he is so closely allied to the person that he is likened to a hair in the other's nostril.  Also said in criticism of one who is made too much of).