n. label; Mark, symbol vt. Label …, call …, classify
vt. Label
tag:
n. Concluding remarks, closing remarks, labels; Tag [with]
vt. The transitive verb attaches [with] to [with]
vt. Give [with] a nickname < Make ... > Call ... <; Make ... >
vi. Follow closely behind
label is usually attached to a commodity or an object, which is a fixed part of the commodity. It refers to a trademark. tag is usually attached to an object at a later stage and has no trademark meaning.