What is the difference between the stem of a plant and the branch of a plant. Is the branch part of the stem?
To answer this question, first, we must define the terms. Major primary plant organs can be characterized as either roots, stems, or leaves. A stem is a structure that contains nodes and internodes (as a previous answer explains), and axillary buds. These buds mean that stems can give rise to more stems, roots, or leaves.
Branches can be defined as stems arising from an axillary bud of another stem. In this way, all branches are stems, but not all stems are branches. Beware of confusing the botanical definition of branches (arising from axillary buds) from the colloquial definition of a branch (a tree branch) because... all tree branches arise from axillary buds, but not all botanical branches are found on trees!
Hope this helps!