The third name in trinomial nomenclature is

The correct option is subspecies.

To understand this, let us look at the structure of scientific naming systems:
1. Binomial Nomenclature: This standard system uses two names to identify an organism. The first name is the genus, and the second name is the specific epithet or species (for example, Homo sapiens).
2. Trinomial Nomenclature: When a species shows significant geographic or physical variations, it is further divided. To classify these variations, a third name is added to the binomial name. The three names, in order, are:
- First name: Genus
- Second name: Species
- Third name: Subspecies (in zoology) or variety (in botany).
For example, in the scientific name for the Indian crow, Corvus splendens splendens, the third name "splendens" indicates the subspecies.