noun
Refers to the body of directors as a group, not the meeting itself.
取締役会は新しい社長を選任した。
The board of directors appointed a new president.
noun
board meeting; meeting of the board of directors
Refers to the meeting itself. Context usually makes the distinction clear.
来週の取締役会でその件を話し合う予定です。
We plan to discuss that matter at next week's board meeting.