sub·branch 
(sŭbbrănch′)
(sŭbbrănch′)n.
A subdivision that has common differentiating characteristics within a larger branch.
- natural childbirth
- natural food
- natural gas
- natural hat trick
- natural history
- naturalism
- naturalist
- naturalistic
- naturalistically
- naturalizable
- naturalization
- naturalize
- natural killer cell
- natural language
- natural law
- natural logarithm
- naturally
- naturalness
- natural number
- natural philosopher
- natural philosophy
- natural resource
- natural rubber latex
- natural science
- natural scientist