Oar (noun)

1. A long pole with a flat blade at one end, used to row a boat or ship.
2. A tool used to propel a boat through water by using a back-and-forth motion.

Origin:

Old english ār, of germanic origin; related to dutch roer and german ruder.

Examples:

1. He rowed the boat with a pair of oars.
2. The oar slipped out of his hand and into the water.
3. She adjusted her grip on the oar before pulling again.
4. The oars were made of wood.
5. The oars were used to maneuver the boat through the rapids.