正字通

Zhengzitong, Chinese character dictionary with 33,549 entries, edited by Ming scholar Zhang Zilie 張自烈|张自烈[Zhang1 Zi4 lie4] in 17th century

zhēng = zh + (e)ng1

first month of the lunar year

zhèng = zh + (e)ng4

straight / upright / proper / main / principal / to correct / to rectify / exactly / just (at that time) / right (in that place) / (math.) positive

to correct an erroneously written character / regular script (calligraphy) / standard form (of a character or spelling)

zì = z + Ø4

letter / symbol / character / word / CL:個|个[ge4] / courtesy or style name traditionally given to males aged 20 in dynastic China

tōng = tu + (e)ng1

to go through / to know well / (suffix) expert / to connect / to communicate / open / to clear / classifier for letters, telegrams, phone calls etc

tòng = tu + (e)ng4

classifier for an activity, taken in its entirety (tirade of abuse, stint of music playing, bout of drinking etc)