This is the 651st most frequent Japanese word.
組
"組" (くみ, kumi) means "group," "set," "class," or "team."
In this usage, '組' (kumi) refers to a bundle or set of items that are linked together, here a set of feathers.
私は青い羽毛でできた組を持っています。
I have a bundle made of blue feathers.
Here, '組' (kumi) suggests an assembly or team, relating to an organized collective, particularly in project creation.
今日は新しい組の制作が始まりました。
Today, the creation of a new assembly has started.
Here, '組' (kumi) is used to indicate groups or sets, in this case, groups of students.