mediator, go-between
媒 centers on a person or thing that connects two sides: a mediator or go-between who facilitates communication or arrangement.
媒 combines 女 (woman) with 某, which likely contributes the sound and the idea of arranging or matching. Historically, matchmaking was often associated with women, giving the character its mediator sense.
A woman 女 stands beside 某, a shape that suggests a certain someone. Picture a woman acting as a go-between, introducing two certain someones to each other.
For バイ, imagine a mediator buying time between two arguing sides: buy -> バイ, and the woman 女 helps them reach an agreement.
medium; media
catalyst
mediation; agency; serving as a medium; acting as an intermediary; acting as a go-between
spirit medium
solvent
refrigerant; coolant
matchmaker; go-between
Computer Mediated Communication; CMC
data medium
data medium protection device
data transformation
news media
recorded (data) medium
photocatalyst; photocatalysis
photocatalysis
optical storage media; optical storage medium
removable media
dispersion medium
(catalytic) promoter
print media