No8=UN↑口and巨DIE

no8=UN↑口and巨DIE (called on the JASRAC database) is Disc 1, Track 8 on the XenobladeX Original Soundtrack (making it the eighth track in 0rCH-SUITE "X"). It is split into two parts; the first plays from the start until 2:28, and the second plays from then until the end. The second part of aBOreSSs is a remix of the second part of this track.

The first part of the track plays in the following cutscenes:
 * The party encounters Volkampf, the Pursuer in.
 * The party first encounters the Prone Scouts in.
 * Nagi notifies the BLADEs of the incoming Ganglion invasion in.

The second part plays in the following cutscenes:
 * The Tainted Sphinx confronts the party in.
 * Doug shows up to help the party fight the Arrow Cinicula during Close Comrades.
 * Elma is notified that the Ganglion have recovered the Vita in.

Etymology
The no8= at the start of the track indicates that this is the 8th track on 0rCH-SUITE "X". Moreover:
 * The kanji 未 is a negation prefix in Japanese that functions similarly to the 'Un-' prefix in English.
 * 矢 is the kanji for 'arrow' (which the character ↑ references).
 * Combining 矢 and 口 into one character results in 知. Including 未 results in '未知' ('michi', 'unknown').
 * '巨' is pronounced 'kyo'. Combining it with 'DIE' results in 'kyodai' ('huge').

Putting these together (assuming 'and' is simply meant to join the two words and ignoring the 'no8=' at the start), the track's name decodes to 'michi kyodai' ('huge and unknown'). This aligns with its JASRAC title.