函 ⇒
邀请函 yāoqǐnghán, [邀請函], invitation letter/CL:封[fēng]
函 hán, [圅], envelope/case/letter, variant of 函[hán]
函数 hánshù, [函數], function (math.)
信函 xìnhán, letter/piece of correspondence (incl. email)
函授 hánshòu, to teach by correspondence
回函 huíhán, a reply (in writing)
函馆 Hánguǎn, [函館], Hakodate, main port of south Hokkaidō 北海道[Běi hǎi dào], Japan
致函 zhìhán, to send a letter
三角函数 sānjiǎohánshù, [三角函數], trigonometric function
函告 函件 hánjiàn, letters/correspondence
函购 hángòu, [函購], mail order
公函 gōnghán, official letter