So what do you guys whink about this definitions:
Transient
A non-repeating waveform, usually of much higher level than the surrounding sounds or average level. Good examples of transients include the attack of many percussion instruments, the "pluck" or attack part of a guitar note, consonants in human speech (i.e. "T"), and so on. Due to their higher-than-average level and fleeting nature, transients are difficult to record and reproduce, eating up precious headroom, and often resulting in overload distortion. Careful use of compression can help tame transients and raise average level, although over-compression will result in a dull, squashed, flat sound to the signal.
Peak
Generally the highest point. In audio this refers in various ways to the maximum audio signal. A sine wave has two peaks per cycle, which represent the maximum or peak amplitude or voltage (one is maximum in the positive direction while the other is maximum in the negative). Complex musical signals have peaks, which represent the loudest sections or moments. Transients in musical material are also referred to as peaks, though they are really a specific type of peak that has a very short duration of time. On a waveform display such as an oscilloscope audio peaks often look like the peaks of a mountain.
Peaking is a word that is sometimes used to describe audio that has gone beyond some specified reference. For example, when the peak LED illuminates on a mixer or recorder the signal can be said to be peaking. This is closely associated with overloading, distortion, and clipping.
Those are taken from sweetwater's glossary
Would the transient be better defined as a sudden raise in level?