"称呼"用英语应该怎么说

在商务信函中正式一点的“称呼”是 appellation

单位名称可以直接说：unit name

而具体到某一个公司，工厂等单位的名称了，可以说：
The Name of Company/ Factory...

称呼

[词性]：vt.vt.vt.
[拼音]：chēnɡ hu
[解释]：
address;
label;
appellative;
apellation;
a form of address;
form of address;
denomination;
designate;
call;
appellation;
style;
1.a title;
an appellation;
a form of address;
the name one wants to be addressed by
2.to call; to name ;
call/address as;
sir
[参考词典]：汉英综合大词典 汉英综合科技大辞典 汉英综合大词典

“称呼”Name
“单位名称”Unit name

Name
Unit name

title
name of ...( like factory, company,etc)

Name
Unit name