Instrumental and karaoke content are related but distinct categories, each with its own naming and genre requirements.
2.19.1 Definitions
Apple defines **Instrumental** as music performed only by instruments, with no vocals or lyrics of any kind — no lead vocals, background vocals, vocal loops, or spoken word. **Karaoke** is defined as an instrumental version of a known song with lead vocals removed or reduced, intended for the listener to perform the lyrics themselves.
2.19.2 The Instrumental flag
Apply the Instrumental flag only to a track containing zero vocal content. A single sung syllable, vocal sample, or background vocal line disqualifies a track from this flag.
2.19.3 Karaoke-specific requirements
Karaoke content must use Karaoke as the primary genre (2.10.2). Per 2.15.5, karaoke titles may reference the original artist using the specific clarifying phrase "Originally Performed By [name]" — this is the one exception to the rule that original artist names must not appear in cover/tribute content.
2.19.4 ISRC requirement
An instrumental version is a distinct recording from its vocal counterpart and requires its own ISRC (see 2.14) — the vocal version's ISRC must never be reused.
2.19.5 Version title format
When releasing both a vocal and instrumental version of the same song on one release, the instrumental version's title uses the standard version notation: "Track Name (Instrumental)". Both versions must have unique titles on the release.
Source: MadDesk article 2.19 (2-19)