the same company; the said firm
Used in business or news contexts to refer back to a company previously mentioned.
同社は来月、新製品を発売する予定だ。
The company plans to release a new product next month.
According to the company, they plan to launch a new product next month.
the same shrine; the said shrine
Used in contexts where a Shinto shrine has been previously mentioned; the kanji 社 can mean 'shrine' in this sense.
同社は毎年、多くの参拝者でにぎわう。
The shrine is crowded with many worshippers every year.
The shrine is said to have been founded in the Heian period.
The company announced the launch of a new service.
同社 refers anaphorically to a company mentioned earlier (often someone else's), while 当社 means 'our company,' used by the company itself.
同社 refers back to 'the same company' whereas 同省 refers back to 'the same ministry', so the two are easy to mix up in news writing.
同氏 refers back to a previously mentioned person, whereas 同社 refers back to a previously mentioned company.
Compound of 同 (どう, 'same') and 社 (しゃ, 'company' or 'shrine').