IPA: /prɛˈzɪdɛnʃəli/
KK: /prɛˈzɪdɛnʃəli/
In a manner that relates to or is characteristic of a president or presidency.
The committee acted presidentially during the negotiations, showing strong leadership.
Presidentially → It is formed from "president" (from Latin "praesidens", meaning sitting before or presiding) and "-ally" (meaning in a manner relating to). The word "presidentially" means in a manner relating to a president or the presidency.
Think of someone who is 'sitting before' ('praesidens') and how they act 'in a manner relating to' their role — that's what presidentially means.