The term 'very brief time' can be described in five different ways, each with a different number of letters. The first is 'TRICE' which has five letters and means a period of time lasting only three days. The second is 'INSTANT' which has seven letters and means an immediate occurrence. The third is 'JIFF' which has four letters and means a very short period of time. The fourth is 'psec' which has four letters and means one trillionth of a second. The fifth is 'twoshakes' which has nine letters and means a very short period of time, usually less than a second.