Is Steve's a common noun

Answer 1

No, the word Steve's is the possessive form of the proper noun Steve, the name of a specific person.

The apostrophe s ('s) added to the end of the proper noun indicates that something in the sentence belongs to Steve.

A common noun is a general word for any person, place, or thing.

Examples:

This is Steve's bicycle.

• the bicycle belonging to Steve;
• the noun 'bicycle' is a common noun, a general word for any two wheeled muscle powered vehicle.

Steve is my brother.

• the noun 'brother' is a common noun, a general word for any male sibling.