In music theory, key is the major or minor scale used to produce a piece of music, a music is called in a MAJOR KEY when it’s based on a major scale, a music is called in a MINOR KEY when it’s based on a minor scale.

A music is in C MAJOR key mean that it’s revolves around the seven notes of the C major scale (C,D,E,F,G,A,B), if it’s in F MAJOR key it uses the notes of the FMAJOR scale (F,G,A,Bb,C,D,E).

Any major or minor scale can be used as a key for a piece of music.

The TONIC

The tonic is the root note of the key, it’s the note on wich a scale is built, for example, the tonic of the C major scale is C and the tonic of the Eb minor scale is Eb.

How Many Keys Are There?

There are 24 keys, 12 major keys and 12 minor keys.

Keys Characteristics

Keys characteristics is the association of musical keys with specific emotions, this mean when a music is in a certain key it generate specific emotions, below a table of main keys and related emotions  :

Key Emotions
C Major innocence, simplicity, naïvety, children’s talk
C Minor Declaration of love and at the same time the lament of unhappy love. All languishing, longing, sighing of the love-sick soul lies in this key.
D♭ Major A leering key, degenerating into grief and rapture. It cannot laugh, but it can smile; it cannot howl, but it can at least grimace its crying.–Consequently only unusual characters and feelings can be brought out in this key.
C# Minor Penitential lamentation, intimate conversation with God, the friend and help-meet of life; sighs of disappointed friendship and love lie in its radius.
D Major The key of triumph, of Hallejuahs, of war-cries, of victory-rejoicing. Thus, the inviting symphonies, the marches, holiday songs and heaven-rejoicing choruses are set in this key.
D Minor Melancholy womanliness, the spleen and humours brood.
E♭ Major The key of love, of devotion, of intimate conversation with God.
D# Minor Feelings of the anxiety of the soul’s deepest distress, of brooding despair, of blackest depresssion, of the most gloomy condition of the soul. Every fear, every hesitation of the shuddering heart, breathes out of horrible D# minor. If ghosts could speak, their speech would approximate this key.
E Major Noisy shouts of joy, laughing pleasure and not yet complete, full delight lies in E Major.
E minor Naïve, womanly innocent declaration of love, lament without grumbling; sighs accompanied by few tears; this key speaks of the imminent hope of resolving in the pure happiness of C major.
F Major Complaisance & Calm.
F Minor Deep depression, funereal lament, groans of misery and longing for the grave.
F# Major Triumph over difficulty, free sigh of relief utered when hurdles are surmounted; echo of a soul which has fiercely struggled and finally conquered lies in all uses of this key.
F# Minor A gloomy key: it tugs at passion as a dog biting a dress. Resentment and discontent are its language.
G Major Everything rustic, idyllic and lyrical, every calm and satisfied passion, every tender gratitude for true friendship and faithful love,–in a word every gentle and peaceful emotion of the heart is correctly expressed by this key.
G Minor Discontent, uneasiness, worry about a failed scheme; bad-tempered gnashing of teeth; in a word: resentment and dislike.
A♭ Major Key of the grave. Death, grave, putrefaction, judgment, eternity lie in its radius.
A♭ Minor Grumbler, heart squeezed until it suffocates; wailing lament, difficult struggle; in a word, the color of this key is everything struggling with difficulty.
A Major This key includes declarations of innocent love, satisfaction with one’s state of affairs; hope of seeing one’s beloved again when parting; youthful cheerfulness and trust in God.
A minor Pious womanliness and tenderness of character.
B♭ Major Cheerful love, clear conscience, hope aspiration for a better world.
B♭ minor A quaint creature, often dressed in the garment of night. It is somewhat surly and very seldom takes on a pleasant countenance. Mocking God and the world; discontented with itself and with everything; preparation for suicide sounds in this key.
B Major Strongly coloured, announcing wild passions, composed from the most glaring coulors. Anger, rage, jealousy, fury, despair and every burden of the heart lies in its sphere.
B Minor This is as it were the key of patience, of calm awaiting ones’s fate and of submission to divine dispensation.