Question

what did the envelope hold ​

Answer 1

Answer:

It holds notes at the sustain level for a fixed length of time before decaying. ... Another common variation in the same vein is the AHDSR (attack, hold, decay, sustain, release) envelope, in which the "hold" parameter controls how long the envelope stays at full volume before entering the decay phase.

Answer 2

Answer:

the envelope was holding the invitation of a party at evening of Monday 18 January by the education department.