Incidentally, I heard that the meeting has been postponed.

incidentally 由 incident（事件）加后缀 -al（形容词后缀）变成 incidental（偶然的、附带的），再加副词后缀 -ly 构成。字面意思是"附带地、偶然地"，引申为"顺便说一句"，用于转换话题或补充信息。