This is the 7601st most frequent Catalan word.
branca
Branch.
Here, 'branca' refers to a physical branch or part of a tree.
La branca de l'arbre és molt fina.
The tree branch is very thin.
In this usage, 'branca' means a subdivision or field within a discipline or study.
La branca de la biologia que estudia els animals és la zoologia.
The branch of biology that studies animals is zoology.
Here, 'branca' again signifies a subdivision or specialization within a profession or academic field.