Correspondence

函件

hánjiàn

(postal or other written communications)

對應 /对应

duìyìng

(agreement of situations or objects with an expected outcome)

對應關係 /对应关系

duìyìng guānxi

(set theory)

書簡 /书简

shūjiǎn

(postal or other written communications)

通信

tōngxìn

(reciprocal exchange of civilities, especially by letters)

通訊 /通讯

tōngxùn

(reciprocal exchange of civilities, especially by letters)

通訊 /通讯

tōngxùn

(newspaper or news stories generally)