1 chief, primary, prime, paramount, main, first, foremost, ranking, pre-eminent, predominant, dominant, prevailing; leading, starring:
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
2 important, prominent, leading, key, cardinal:
Cuba is a principal source of sugar.
3 owner, proprietor, chairman, chairwoman, chairperson, (managing) director, head, president, chief, chief executive officer, CEO, manager or Brit manageress, superintendent, supervisor, Colloq boss, US (head or chief) honcho:
We should talk to the principals about buying that company.
4 dean, director, Chiefly Brit headmaster, headmistress, master, rector, (vice-)chancellor:
His appointment as principal is for a two-year period.
5 (working) capital, capital funds, resources, investment, backing, (cash) reserve(s), assets; money:
She is fortunate to be able to live on the income from her investments, without touching the principal
6 star, lead, heroine, hero, leading lady or man, leading role, main part; diva, première danseuse, premier danseur, prima donna, prima ballerina:
The principal in the ballet company was a Russian.