1. most important; main
2. first in order of time or development
3. basic or fundamental

1. a preliminary election to select candidates
Usage: politics
2. a primary school
Usage: British

Examples

• The primary reason for the delay was bad weather.
• Safety is our primary concern.
• Children learn primary colors in art class.
• The primary source of income for the family is farming.
• She won the Democratic primary by a large margin.
• The candidate campaigned hard before the primary election.
• He attended the local primary until age eleven.