合併【がっぺい】
merger (of companies, towns, etc.), combination, union, amalgamation, consolidation, coalition, fusion, annexation, affiliation, incorporation
併用【へいよう】
combined use, using together (with), using jointly, using at the same time
併合【へいごう】
merger, joining into one, amalgamation, melding, merging, annexation, absorption
併記【へいき】
writing side by side, writing (down) together, writing (down) both
併発【へいはつ】
concurrence, coincidence, complication (in illness)