Rocker (noun)

1. A person who is a fan of rock music or culture.
2. A person who participates in the rocker subculture, characterized by a rebellious attitude, wearing leather jackets and riding motorcycles.
3. A device that rocks or swings back and forth, such as a rocking chair or a rocking horse.

Origin:

Rocker is derived from the word "rock" which comes from the old english word "roccian" meaning "to move back and forth, sway".

Examples:

1. He's a rocker, he loves to listen to rock music.
2. She's a rocker, she likes to wear leather jackets and ride motorcycles.
3. I love to sit on the rocking chair and relax.
4. The little girl loves to ride on the rocking horse.
5. The baby falls asleep on the rocking crib.