CONCERT PITCH: A standard decided upon by some bearded herberts in 1960 so everyone could agree what to tune their instruments to. Concert pitch puts the A above middle C on the keyboard (or A string on a guitar) at precisely 440Hz. If you tune your guitar to an electronic tuner, tuning fork, or pitch pipe this is what you should end up with.

CROTCHETS AND CO: Each of the strange black marks, or notes, on proper written music has a name which relates to its duration. They don't dictate how long a note should last in every circumstance — you may be playing slow or fast — but they do establish how long those notes last compared to each other. A rigid ratio, if you like. The longest is a breve (not popular) but the main unit is the semibreve which equals two minims; one minim equals two crotchets; one crotchet equals two quavers; one quaver equals two semiquavers; one semiquaver equals two demisemiquavers; one demisemiquaver equals two hemidemisemiquavers. Pause for breath. Here is a rare instance of Americans being more sensible; they call a semibreve a whole note and divide down from there so that a crotchet is a quarter note and so on.

DOTS AND TIES: A nifty way of extending written note lengths, to produce timings not easily covered in the crotchet listing. Done either by tying two notes together to get a bastard length from their combined values, or by adding a dot to increase a note length by half as much again.

INTERVAL: The distance (in other words difference in pitch) between two notes. For example, C to G is a fifth — start counting from C and G is five notes above it in that popular A, B, C, D, E, F, G scale. Fourth, fifth and octave (eighth, geddit?) intervals are prefaced 'perfect' thanks to their pure-sounding relationship; the others are prefaced 'major'. However, if a major is flattened by a semitone it becomes a 'minor'. Flattening a perfect or minor interval down a semitone makes it a 'diminished', sharpening a semitone is an 'augmented'.

INVERSION: Fiddling around with the shape of the chord. In other words, playing exactly the same notes but in a different pattern elsewhere on the fretboard or keyboard. Adding a bass note to an existing chord that happens to be the third of that chord makes the chord a 'first inversion'. Doing the same with the fifth makes it a second inversion.

KEY SIGNATURE: A series of little squiggles at the front of the stave (or further on) to tell you what key the following bit is in. A flat or sharp symbol is written on the line or space of the note which is sharpened or flattened in that key. You can work out the key (other than if you're flash and just know) by noting the position of the last squiggle to the right in the key signature. Major sharp keys = keynote is one note above last sharp symbol; major flat keys = keynote is four notes above last flat; minor sharp keys - one note below last sharp symbol; minor flat keys = two notes above last flat symbol.

LEDGER LINES: These are extra lines added above or below the normal stave if you've got notes to write on them that are beyond the normal range.

REST: Time to grab a quick few paragraphs from Making Music, indicated in the written music by special signs equivalent to note lengths — they say, "Stop playing for this much time."

ROOT NOTE: The fundamental note of a chord which gives it its name — eg the root note of a C major chord is C.

SCALE: An arrangement of notes in order of pitch, running from a root note to its octave, either upwards or downwards. The 'shape' these notes make on the stave and the pattern of intervals between them determine whether the resulting scale is major or minor. A 'chromatic scale' is a very useful term — it uses all the notes between a root note and its octave, so is brilliant for bluffers. "No, I didn't play out of tune, I was using a chromatic scale," for example.

STAVE (sometimes called a 'staff'): The five parallel, horizontal lines on which the notes are written. The higher its position on the stave, the higher the pitch of the note. Being western we read the notes from left to right and play them in that order (with luck). Originally the stave had 11 lines but was split in two for easier reading. A treble clef at the start of the stave indicates notes running from E on the lowest line up to F on the top (remember this: Every Good Boy Deserves Food). With a bass clef at the front, notes range from G (lowest line) to A at the top (remember: Great Bassists Do F All).

TIME SIGNATURE: A code looking like a vulgar fraction at the start of the stave. The bottom number tells you the type of beat (a crotchet or quarter note equals '4'; a quaver or eighth note equals '8' and so on). The top number tells you how many of these beats per bar. Anything other than 4/4, 3/4 or 6/8 tells you it's jazz.

TONE/SEMITONE: A tone equals two semitones; and a semitone is the shortest distance you'll find between two notes in Western music — ie, from one fret to the next, or from one key to its neighbour. Drummers don't have to worry about it much. A tone can also be represented as an interval of a major second.

TRIPLET: A '3' written over a group of three notes means you have to play these three notes in the time normally occupied by two equivalent notes. Tricky but neat.

TRIAD: Basic three-note arrangement forming either a major chord made up of root note plus a major third (four semitones away from the root) and a fifth, or a minor chord made up of the root note plus a minor third (three semitones away from root) and a fifth. Adding notes to the basic triad can make 7th chords, 11th chords and so on, drawing their names from the intervals between these extra notes and the root note.