oak (OHK)
noun.

tree native to the Northern Hemisphere.

oar (OR)
noun.

long paddle used for rowing.

oasis (oh-AY-sihs)
noun.

area made fertile by a source of fresh water in an otherwise arid region.

Read more in the NG Education Encyclopedia

oath of office (OHTH uv AH-fihs)
noun.

public promise a person makes before taking a job or responsibility.

oatmeal (OHT-meel)
noun.

rolled or ground oats mixed with water or milk.

oats (OHTS)
noun.

type of edible grass.

obelisk (AH-buh-lihsk)
noun.

tall, tapering, four-sided stone structure.

obese (oh-BEES)
adjective.

severely overweight, often defined as an adult who has a body mass index (BMI) of 30 or higher.

obesity (oh-BEE-sih-tee)
noun.

medical condition where excess body fat increases risk for disease and death.

obey (oh-BAY)
verb.

to follow rules, ideas, or instructions.