An auditory tone of low pitch or volume.
A pale colour, or one seen underneath another colour.
A low state of the physical faculties.
An implicit message perceived subtly alongside, but not detracting noticeably from, the explicit message conveyed in or by a book, film, verbal dialogue or similar (contrast with overtone); an undercurrent.
To accompany as an undertone.
To say or speak in an undertone.
To present as less important, noticeable or prominent.
Any musical instrument that produces sound when air flows through it; a woodwind instrument or brass instrument.