What it means
ちなみに introduces additional information that is related to what has just been said but is not essential to the main point. It is commonly used at the beginning of a sentence and can be translated as “by the way” or “incidentally.” The added information is usually connected to the topic, so ちなみに is more than a completely abrupt change of subject. It can be used in both familiar and polite speech; the surrounding sentence determines the register.
Usage note
ちなみに is a discourse marker, not a normal adverb that directly modifies a verb or adjective. It is often followed by a comma in writing. Do not confuse it with ついでに, which means doing something while taking the opportunity to do something else.
How to use it
ちなみに、来月の会議は午後三時から始まります。
By the way, next month's meeting starts at three p.m.
ちなみに、来月の会議は午後三時から始まる。
By the way, next month's meeting starts at three p.m.
Example sentences
この図書館では毎月新しい本が紹介されます。ちなみに、紹介された本は一階の棚で一週間借りられます。
New books are introduced at this library every month. By the way, introduced books can be borrowed for one week from the shelf on the first floor.
来週の会議は午後二時から始まります。ちなみに、会議室は本館の三階