in session

in session

Currently gathered and in the process of conferring about or working on some thing. Hey, no one is allowed in there while the meeting is in session! I haven't been able to talk to the lawyer yet because court is still in session.
See also: session
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

in session

[of a court, congress, or other organization] operating or functioning. Use of cameras is forbidden while the meeting is in session. The spectators must remain quiet while court is in session.
See also: session
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also:
References in classic literature ?
The ordinary power of appointment is confined to the President and Senate JOINTLY, and can therefore only be exercised during the session of the Senate; but as it would have been improper to oblige this body to be continually in session for the appointment of officers and as vacancies might happen IN THEIR RECESS, which it might be necessary for the public service to fill without delay, the succeeding clause is evidently intended to authorize the President, SINGLY, to make temporary appointments "during the recess of the Senate, by granting commissions which shall expire at the end of their next session." Second.
A DISTINGUISHED Naturalist was travelling in Australia, when he saw a Kangaroo in session and flung a stone at it.
Probability of individual detection declined in that study, from 0.93 in session 1 to 0.11 in session 5 (Belant et al.
14, by which time Congress was back in session and ready to take up a citizenship bill that could turn the case from an immigration question back into a custody battle, which could be abjudicated in Rodriguez's Miami court.
As if these opportunities were not appealing enough, a terrorist would have plenty of chances to wreak havoc at one of the many social receptions held each night Congress is in session. On the House side, these gatherings are often held in the Rayburn Gold Room or the Cannon Caucus Room, and metal detectors are rarely posted at them.
CONSUMER watchdog Healthwatch Kirklees is inviting people to air their views about NHS services at face-to-face drop in sessions in Huddersfield and Dewsbury.