The phrase "last word" means having the final say or being the final statement in a conversation or argument. It refers to the opportunity to speak or express one's opinion after everyone else has spoken. Full definition
Not only will these delightful brown characters insist on being a part of every activity in the household, they also insist on having the very last word on everything. (cfa.org)
It has been the first and last word in veterinary medicine for over half a century so adding another «first» is nothing new. (thedogplace.org)
I am going to do my best to hold your attention until the very last word of this column. (discovermagazine.com)