Asia, rank next, come after, -ous
亜 centers on the idea of being secondary or coming after something else: ranking next, following in order, or being a lesser version. The meaning 'Asia' is a specific abbreviation, and '-ous' reflects a suffix-like sense of being characterized by something, which fits the idea of being attached to or derived from a primary thing.
亜 is the modern simplified form of 亞. The older form is a pictograph of a multi-room building or a layout with a central hall and side rooms, suggesting a secondary or subordinate position. The modern simplified shape retains the general outline but obscures the original architectural image.
The shape looks like a top bar with a boxy base, like a secondary shelf placed below the main one. Whatever is on the lower shelf comes after or ranks next to the top shelf.
For ア, imagine a runner-up standing on the lower shelf, sighing 'Ah...' because they came second. The sound 'Ah' cues ア, and the runner-up is the one who comes after.
sub-; second-rate; inferior
East Asia; the Orient
zinc (Zn)
subtropics
flax (Linum usitatissimum); linseed
chalk (rock)
raising Asia; development of Asia; making Asia prosper
(inferior) imitator; epigone; poor imitation; copycat
sulfurous acid; sulphurous acid
Kia (car company)
flaxseed; linseed
Asia University
subarctic zone; subpolar region
The Dong-a Ilbo (Korean newspaper)
Anabantoidei (suborder of labyrinth fish)
Caniformia
Indian subcontinent
Ruminantia; suborder of ruminants
Caseasauria; Pelycosauria suborder of early synapsids
Caseasauria; suborder of early pelycosaurs