adjective
The principal reason I'm here is to see you. The principal food of the people is corn. The principal role was sung by Pavarotti
Cuba is a principal source of sugar
noun
We should talk to the principals about buying that company
His appointment as principal is for a two-year period
She is fortunate to be able to live on the income from her investments, without touching the principal
The principal in the ballet company was a Russian
US