What does it mean when congress says to strike the last word

It means he or she wants to speak

Explanation:

There might be deliberation on a particular motion in congress, or there is an argument in congress about a particular topic. When a congress man or woman states " I move to strike the last Word" it  means he or she wants to speak and once it is granted, he or she can speak.

NB; This is only said in congress like in the united states.

the president has the power to appoint federal judges, ambassadors, and other "principal officers” of the united states, subject to senate confirmation of such appointments.