共同cooperation同一identity同時simultaneous(ly)同様identical同僚coworker合同combination同格the same rank一同all present混同confusion同the same同意agreement同感agreement同級the same grade同居living together同士fellow同志same mind同情sympathy同調sympathy同等equality同封enclosure (e.g. in a letter)同盟alliance
封 ふう
封筒envelope同封enclosure (e.g. in a letter)封seal封鎖blockade