As an expert in music theory, one hears the general public use music terminology wrongly on a daily basis. This is understandable since most people nowadays grow up with pop and rock music without being properly educated in music theory. This undesirable situation is rectified herebelow; the collection of misused terms may be expanded at any time as needed.
Persons who prefer colloquial meanings to real meanings are advised to look away while reading this article, as the exposure to so much pure, undiluted truth might irritate them.
The popular misinterpretations of the term "absolute hearing" or "absolute pitch" are (1) that it means you have very good musical hearing and (2) that it is useful or even required in order to be a good musician. In reality, absolute hearing means that you can recognize a musical tone — such as C, F sharp, or D flat — without needing to compare it to a reference tone. You have the tonal reference frame built-in to your brain so to speak.
Absolute hearing is neither required nor necessarily beneficial for musicians. What musicians require is relative hearing; that is, the ability to recognize the intervals between tones rather than the tones themselves. It is the intervals that make up melos and harmony. The possession of absolute pitch may even be disadvantageous for a musician, for instance in the case of a piano that is tuned a bit higher or lower than the standard tuning. A person with absolute pitch may be confused then because one is constantly hearing different tones than expected, while a person with relative hearing has no problem as long as the intervals between the tones are correct. Relative pitch is the type of hearing that is positively relevant in music. The observation that a particular musician has absolute hearing is in no way a recommendation as to one's musicianship.
On stringed instruments like violin and guitar, the strings run over two parts that define their effective scale length: one on the sound body called "bridge" (or "bridge saddle" for the precise part of the bridge that supports the strings) and one at the head of the neck called by words like "nut" or "comb". The latter has slots for the individual strings so that it actually looks like a comb. The tradition to call the contraption on the sound body "bridge" is reflected in the music term sul ponticello ("near the little bridge") which instructs the player to pluck or bow the strings near the bridge.
Sometimes these term are confused; in the Netherlandic language for instance it is customary to call the nut of a classical (nylon-string) guitar "brug" ("bridge") and the bridge saddle of such a guitar "kam" ("comb"), and many instruction books for classical guitar contain this inverted terminology. The logic in the previous paragraph though supports the correctness of the terminology as defined in that paragraph.
When asked to perform a rhythm, people tend to produce a short repeated musical motif, and music consisting of and emphasizing such repetition is called "rhythmic". Such a repeated motif is properly called ostinato though. The actual meaning of "rhythm" is "the succession of relative durations of notes and/or rests"; in other words, the division of time. Do note that rhythm does not require repetition at all. For example, the most rhythmic music known is probably Gregorian chant, which is devoid of repetition altogether.
And incidentally, note that "note" refers to the duration aspect of a musical sound, while "tone" refers to its pitch aspect.
The words scale and mode are generally confused such that "scale" tends to be used for any type of ranked set of tones. There is a conceptual difference though: "Scale" properly refers to the major and minor variants of classical functional tonality. These are hierarchic systems wherein one tone, the "tonic", is more important than the other tones. Other steps in the hierarchy are the subdominant and dominant. This system of "tonal" music prevailed in the baroque era and classical period, and began to be broken down during the Romantic period. Pop and rock music, blues, and older jazz styles (Dixie, bob, cool) also employ hierarchic tonality and thus use scales; they are strictly tonal. It is a popular fallacy that jazz musicians in the named styles use "modes" for improvisations. They do not.
"Mode" is connected to more free-floating music without a tonic and without a hierarchy of functions; such music is called "modal" as opposed to "tonal". No tone is more important than the other ones of the mode. This system is typical of medieval and Renaissance music, but also of later jazz ("modal jazz") and jazz-rock fusion. The composer Erik Satie is also known for reintroducing modes in his music. In contemporary music, the concept of "mode" is no longer restricted to the original medieval modes, but may refer to any ranked set of tones without hierarchic functions.
"Tone" is often used incorrectly when "sound" (timbre) is meant. It actually refers to the pitch aspect of music; to "how high" a musical sound is. Examples of tones are C, C sharp, F flat, and A double sharp. This misuse of "tone" is a form of Germanism; the German Ton means "sound". A typical example of this misuse is the term "tone controls" for the sound controls of audio equipment.
Incidentally, sound (timbre) refers to the character of a musical sound, which is physically defined by its composition in terms of harmonics; for instance, a sound may have only the ground tone (first harmonic, sinus tone), or the ground tone with odd-numbered harmonics ("hollow" sound), or the ground tone with both odd- and even-numbered harmonics ("rich" or "full" sound).
The conflation of tremolo and vibrato goes back to at least the 1950s, when manufacturer Leo Fender equipped guitars (called "Stratocaster") with a vibrato device, which he incorrectly called "tremolo bar". Around the same time, he produced amplifiers such as the Bandmaster, featuring an actual electronic tremolo channel, which was incorrectly labelled "vibrato".
For clarity, "tremolo" means "fast tone repetition", "fast alternation between two or more discrete tones", or "fast amplitude modulation" (which is how it is technically realized in electronic equipment). "Vibrato" on the other hand means "continuous pitch modulation".
Incidentally, the later, more advanced implementations of the guitar vibrato arm are also capable of extended glissando effects, informally termed "dive bomb". And the "tapping" technique utilized by many rock guitarists is highly suitable for producing a tremolo effect in the sense of "fast alternation between two or more discrete tones".
"Voice leading" or "part writing" is one of the hardest musical concepts to understand if one has no active experience as a composer and instrumentator or orchestrator oneself. It refers to the horizontal aspect of music (melody), not the vertical aspect (harmony). It is the way in which the individual "voices" or "parts" of a chord progression or polyphonic piece progress.
To understand this, one needs to learn to conceive a chord progression as a number of separate melodies sounding at the same time. If each chord consists of four tones, the chord progression is really four superimposed melodies (called "voices" or "parts"). The top voice is typically called soprano, the second alto, the third tenor, and the bottom one bass. The melodic progressions of these respective voices are what one calls "voice leading" or "part writing", and each of the voices has to be a proper melody in its own right in order for the chord progression to sound well. This insight is one of the things that separate the competent composer and instrumentator from the dilettante. Incompetent dilettantes are betrayed by their practice of putting one chord after another without taking voicing into account, which results from their not knowing or understanding the concept of voice leading. Incompetent composers write successions of chords, competent composers write (simultaneous) melodies. Bad composers think in harmonies, good composers think in voices.
In addition, there exists a confusing term "voicing", which refers to the manner in which the tones sounding at a given moment are divided over the conceptual voices (for instance soprano, alto, tenor, bass), or the manner in which the voices are assigned to the various instruments.