1. Noun

   presence (e.g. of an observer); observation; observer; witness

2. trading session (at an exchange)

   Stock market

3. rising from a crouch to charge; initial charge; face-off

   Sumoesp. 立ち合い

Also written 立ち会い【たちあい】tachiai、立会【たちあい】tachiai、立ち合い【たちあい】tachiai