meet, party, association, interview, join
會 centers on people coming together: meeting, gathering, joining, or forming an association. An interview is a formal meeting, and a party is a social gathering.
會 is the traditional form of 会. It combines 亼 (a lid or cover) with 曰 and 罒, suggesting words or breath gathered under a cover, conveying the idea of meeting or assembling. The exact historical development of the lower components is uncertain.
The top 亼 looks like a roof or cover, and the middle 罒 resembles a net or gathering of lines. Picture people gathering under one roof, their voices (曰) mingling together in a meeting or party.
For カイ, imagine a lively meeting where everyone shouts 'Hi!' as they join: 'Hi' sounds like カイ, and the gathering is full of greetings.
Kudō-kai (yakuza group)