main; principal; major; primary

Tax cuts are often used as a major fiscal tool to stimulate the economy.

The water mains burst due to the earthquake.

The main duty of a priest is to preach in church.

They also have ‘You can be serious without a suit’ as one of their key beliefs.

In some rural areas, the Internet is important for agricultural information, as well as being particularly useful for the purposes of agricultural production technologies and pricing.