Timeline

From Audacity Manual

The ruler above the tracks measures time. Depending on zooming the ruler may span minutes of audio or give a 'close up view' of a few seconds.

The ruler is also marked up with various symbols:

• The selected range: is shown as a shaded region on the ruler.
• The playback cursor: is shown as a green triangle.
• The record cursor: if present is shown as a red triangle.
• Quick-Play range: A selectable time range that always plays "on demand", shown by arrowheads with a line connecting them. Select a range on the ruler by dragging with the mouse, and that range will play as soon as you release the mouse, even if audio is already playing elswhere. Neither an already selected region or the cursor is affected by defining a Quick-Play range. For other methods of navigating to playback points or areas, see Playing and Recording.

The image of the ruler shows a selection and to the right a quick-play region with the playback cursor part way through playing it.