The collective multitude of angels understood as the army or assembled company of heaven, often represented in dense celestial groups around Christ, the Virgin, or scenes of glory.
The Heavenly Host is the collective company of angels praising and serving God. In Christian imagery it may appear as an immense multitude surrounding Christ, the Virgin, a throne, a mandorla, or a burst of heavenly glory.
Etymology
Host from Latin hostis and later ecclesiastical usage meaning an army or multitude.
Sculptor Notes
Massed angels require hierarchy of scale and depth. A successful sculptural host is not a pile of repeated heads and wings: foreground figures, half-emergent forms, relief depth, cloud masses, and diminishing scale can create a convincing celestial continuum.
References
https://www.vatican.va/content/catechism/en/part_one/section_two/chapter_one/article_1/paragraph_5_heaven_and_earth.html