The seed of cotton is called 'cotton seed'.The pod that contains the cotton seed and the cotton fiber is called a 'boll'.
The source of the cotton fibre is the cotton plant which bears a seed pod which contains the cotton seed and the cotton fibre. This is a very ingenious packaging that nature has devised for the cotton seed. The seed is first wrapped in cotton fibre and then it is covered in a harder outer pod cover. It grows in places with high summer temperatures and humidity.
The ripe, open seed pod (the cotton boll).
pod
Cotton is part of the seed of the cotton plant. The cotton is white fluffy strands attached to the cotton seed that allows the seed to catch the wind and be dispersed. We collect these fluffy bundles just as the pod opens and scrape off the seed, keeping the cotton fluff which is combed and twisted into cotton thread.
Do you mean what are cotton bolls? Cotton boll is the name of the rounded seed pod of the cotton plant. The fibres harvested for cotton develop within the boll and are part of it.
pod/ hull
pea
The seed pod protects and holds the seeds.
kapok is from the kapok tree. it has a seed pod similar to the cotton tree pod and the kapok ( as with the cotton ) is the fibre from inside the pod it is generally used for matress, toy and pillow stuffing
Cotton is softer. Additionally, cotton is a cellulose fiber taken from the seed pod of a plant. Wool is a keratin fiber and is a variety of fur that sheep have.
seed pod