A quarter, one of four equal parts of a whole.
The fourth gear of an engine.
A musical interval which spans four degrees of the diatonic scale, for example C to F (C D E F).
The person or thing in the fourth position.
The ordinal form of the number four.
To agree with a proposition or statement after it has already been thirded.
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.