Headjoint
The top section of a flute or oboe, carrying the embouchure hole or reed socket.
What it means
The headjoint is the topmost, detachable section of a woodwind instrument. On the flute it carries the embouchure hole, against whose edge the air stream is split; on the oboe and related instruments it holds the reed or its staple.
Musical use
On the flute, the headjoint's shape, wall thickness and bore affect tone color, response and projection more than any other single part, which is why professional flautists often pair a headjoint from one maker with a body from another. On the oboe the headjoint is usually a fixed part of the topmost body section and carries the seat for the reed. It differs from the mouthpiece of a clarinet or saxophone, which likewise holds the reed but is built differently and is rarely tuned as a separate tonal component.
Performance practice
When tuning a flute, pull the headjoint out slightly or push it in to adjust overall pitch — the further out it sits, the lower the pitch.