To multiply by four.
To increase by a factor of four.
To provide four parallel running lines on a given stretch of railway.
Being four times as long, as big or as many of something.
A figure-skating jump with four revolutions in the air.
Something that is four times the usual number, amount, size, etc.
To replicate four times; to make fourfold; to quadruple.
in quadruplicate: four times over, in four copies
four times over, multiplied by four
having four parts