Something that is four times the usual number, amount, size, etc.
A figure-skating jump with four revolutions in the air.
Being four times as long, as big or as many of something.
To multiply by four.
To increase by a factor of four.
To provide four parallel running lines on a given stretch of railway.
Quadrilateral.
An aspect of two planets with regard to the Earth when they are distant from each other ninety degrees, or a quarter-circle.