both, old Japanese coin, counter for carriages (e.g., in a train), two
両 centers on the idea of a pair or two things together: both, two, or a matched set. The counter for carriages and the old coin sense are specific applications of this paired or double concept.
両 is the modern simplified form of 兩. The older form 兩 likely depicted a pair of something, such as two yoked horses or a balanced scale, representing the idea of two or both.
The shape looks like a balanced pair: the top line is a connecting bar, and the inner strokes are two matching halves. Picture a scale with two equal sides, representing both or two.
For リョウ, imagine a pair of lions (ライオン) standing together: the first syllable 'ryo' from a made-up word 'ryon' cues リョウ, and the two lions represent both.
both (hands, parents, sides, etc.)
both; both sides; both parties
(wheeled) vehicle; car; (railroad) car; (railway) carriage; rolling stock
parents; both parents
both hands; both arms
pair; the two; both persons; both things
compatibility; coexistence; standing together
both countries
both sides; two sides; double-sided
both sides
both feet
both arguments; both opinions
change; money exchange
both ends; either end; both edges
both days; two days
both houses of parliament; both upper and lower house
both persons
two wheels
both wings; both flanks
two great men
one vehicle
both (political) parties
both banks (of a river)
both eyes