Final answer:
The term for a branch that runs parallel to the main branch is generally referred to as a 'side branch,' though different disciplines may have specific terms.
Step-by-step explanation:
The name given to a branch that runs parallel to the main branch is called a side branch. In various disciplines, however, terminology can vary. For example, in electrical circuits, you might encounter a “parallel branch,” but in the context of biology, such as in the branching of a tree or the structure of a plant, the term “side branch” is more commonly used. It's important to understand that each field may have its own nomenclature for similar concepts based on context and specificity of the terms.