join, get together, unite, collective
併 centers on bringing separate things together into one: joining, uniting, or forming a collective. The idea of getting together applies to people, objects, or actions.
併 combines 亻 (person) with 并, which likely contributes both sound and the idea of combining or pairing. The exact historical development of 并 is uncertain, but the character as a whole expresses people joining together.
A person 亻 stands beside 并, a shape that looks like two things joined side by side. Imagine two people coming together to form a united group.
For ヘイ, picture a group of people joining together to say 'Hey!' in unison: Hey -> ヘイ, and their collective voice unites them.
combined use; using together (with); using jointly; using at the same time
merger (of companies, towns, etc.); combination; union; amalgamation; consolidation; coalition; fusion; annexation; affiliation; incorporation
joint establishment (esp. schools of different levels or different courses of study); establishment as an annex (e.g. of a school); juxtaposition; placing side by side
merger; joining into one; amalgamation; melding; merging; annexation; absorption
writing side by side; writing (down) together; writing (down) both
complication
double play
concurrence; coincidence; complication (in illness)
concurrent selling (e.g. of old and new models); selling (related products) alongside each other
coexistence
combining a pair of events; joint
applying to enter more than one school
merger
to have two things (at the same time) (e.g. good and bad points); to also have something (in addition to something else)
to use jointly; to use at the same time
to consider together
concurrent offenses; concurrent offences
annexation; absorption; merger; swallowing up
having both (at the same time); possessing together
combined treatment; combination therapy