1constituting number four in a sequence; 4th:the fourth and fifth centuriesthere were three bedrooms, with potential for a fourth
the fourth finisher or position in a race or competition:he could do no better than finish fourth
the fourth (and often highest) in a sequence of a vehicle’s gears:he took the corner in fourth
chiefly British the fourth form of a school or college.
fourthly (used to introduce a fourth point):third, visit popular attractions during lunch; fourth, stay late
Music an interval spanning four consecutive notes in a diatonic scale, in particular (also perfect fourth) an interval of two tones and a semitone (e.g. C to F).
Music the note which is higher by a fourth than the tonic of a diatonic scale or root of a chord.
2chiefly North American a quarter:nearly three fourths of that money is now gone
the fourth estate
the press; the profession of journalism:she is reticent when it comes to members of the fourth estate
[originally used humorously in various contexts; its first usage with reference to the press has been attributed to Edmund Burke but this remains unconfirmed]
the fourth wall
the space which separates a performer or performance from an audience.
the conceptual barrier between any fictional work and its viewers or readers:he breaks the fourth wall by having Sam refer to the script and the play he’s acting in
[originally used of the proscenium opening in a theatre through which the audience sees the action of a play]
