(uncountable) Relatively highest importance. / (countable) Item of highest importance.

Of or relating to a hierarchical system that progresses from a single, large basic unit to multiple, smaller subunits. / Produced, controlled, or directed by those at the top of the hierarchy.

(accounting) Total sales or revenue.

(military) A flag on the edge of a minefield. / (linguistics) The line connecting individual letters in Devanagari.

Channel Island milk.

the typescript of a document that has carbon copies underneath

(chiefly US, idiomatic) The maximum amount of money that an item, service, or worker is worth; a very high price.

The highest gear that is available in a motor vehicle or car.

That serves as an addition

An addition. / A serving of drink used to top up an existing glass. / (insurance) An additional premium paid over the initial premium in order to increase benefit values.