اَلْمَجَالِسُ بِالْأَمَانَة (رواه أبو داود)
Gatherings are with trust.
This hadith has largely fallen under the category of “forgotten Sunnah” for much of the ummah today. In Islam, it is considered a given that anything said to other people is private by default. This is opposite to how much of the Western world operates, where all communications are considered to lack privacy unless people enter into an agreement of privacy – and even that is violated quite frequently.
The exceptions to the rule would be gatherings that are considered public by nature, such as Islamic classes or halaqas where an open invitation is sent to the community. Even then, it is better to only relate what is part of the scheduled talk and not things said as an aside, especially if they are personal.
مجالس (majaalis) is the broken plural for مجلس (majlis) which comes from the root جلس (jalasa), meaning “to sit”. Basically, a majlis is any sort of a sitting with two or more people.
An أمَانَة (amaanah) is a trust, and it comes from the root امن (amuna) which means “to be faithful, reliable, trustworthy, to be safe, to feel safe”. Other words from this root include آمين (aameen, related to the English word amen), and مؤمن (mu’min) which means a believer.