Definitions:
coming after, less important than, or resulting from someone or something else that is primary

(of an organic compound) having its functional group located on a carbon atom which is bonded to two other carbon atoms.

denoting or relating to organisms in a particular community that belong to the second trophic level among its consumers, and consume primary consumers

relating to or denoting the output side of a device using electromagnetic induction, especially in a transformer

a secondary school.

a secondary coil or winding in an electrical transformer.

a secondary feather.

the secondary or mesozoic era.