Child Pays For Parent (CPFP)
From Trezor Wiki
CPFP (Child Pays For Parent) transaction is one where you pay a high fee to incentivize miners to also confirm the unconfirmed transaction from which you are drawing the inputs i.e. the parent transaction.
CPFP with Trezor in Electrum[edit]
It is possible to incentivize miners to confirm incoming transaction using Electrum app. For more information please read Electrum docs:
My bitcoin transaction is not confirming what can i do
How to do a manual child pays for parent transaction
See also Replace-by-fee (RBF)